Few things:

- 3D printer. I want to pay $150~ for the machine and no more than $20 for a spool of material to feed into it. I also want some kind of "market" where people can trade free and paid-for 3D models I can grab and print.

- Home circuit-board printer. Now obviously this thing wouldn't have very high density and couldn't do 3D/multi-dimensional circuits like the big boys can. I'm more thinking of being able to have a piece of metal and to "melt" away all the excess until you're left with the tracks and empty positions for you to slot in components by hand.

- A PC monitor which can display at 2880x1800 but which Windows thinks is displaying at 1400x900 so you get twice as many pixels per every element of the screen (e.g. text). Currently increasing resolution decreases the size of screen elements which is useless. 1920x1080 is almost too small to see.

- A replacement for the "gas lift" in office chairs which is of fixed length. I keep having the gas lift fail and the chair loses height very slowly throughout the day (even in $150+ chairs which claim they can support someone weight 350 pounds!). I want a bar the same size as a gas lift, you decide how high you want your chair, you buy the appropriate bar, you install it, and it never moves again. Or a twist-to-adjust height option.

- A comprehensive alternative to Skype. Video calling, VoIP<->telephone, better software than Skype, much better support. This alternative also has to be easy enough for "my mum" to use. No getting her to download three different suites of software and then configure them together (I'm look at you Open Source everything ever). I'd pay a fair bit for this, I already pay Skype a fair bit... I have two subscriptions, two numbers, and spend credit with them too.

(submitting each idea as its own comment)

A centralized content-consumption queue with comparison shopping and price alerts.

E.g. back in the days when Netflix was DVD-only and had a decent selection of films, you could add practically anything ever screened to your Netflix queue, where it was captured basically forever.

Nine times out of ten the movie I want isn't available on Netflix Watch Instantly, so I have to add it to some todo list somewhere and promptly forget about it. I also usually can't be bothered to see if Amazon or iTunes has it, and certainly can't be bothered to check back every so often to see if it went on sale.

The same goes for physical and electronic books, music, and even stuff.

I would expect this service to be free (paid for by Amazon/iTunes/etc. kickbacks), or at most cost me some privacy. Advertisers would probably pay top dollar to put their deals in front of users who are already planning to buy their stuff at some point in the future.

An affordable car stereo with a UX that doesn't feel like it was made in 1987:

- A good display. Even a decent display. Something that isn't worse than the mobile phone I bought in 1998.

- A big knob or two for navigation (if I wanted to operate a touchscreen while driving I'd just use my phone)

- AM/FM, Bluetooth and iPhone support. No need for optical media.

- A reasonably well thought-out control layout (i.e. unlike my Dual XML-8150)

I'd expect to pay around $199 or $299. I would probably hold my nose and pay $499 if they really nailed it (see original iPhone, Nest thermostat, etc.)

A banking service with "micro-accounts". E.g. each month I would put $80 in my "buy a new laptop every couple of years" account, and each day I would put $20 in my "feed and entertain myself" account.

Every couple of years I could buy myself a laptop without getting a pointless "You spent $1500 on computing this month! You usually spend $10! Ermahgerd!1!!" alert. And when I'm thinking about treating myself to a night out, I can quickly see how guilty I should feel about doing so.

Have you seen SmartyPig? http://www.smartypig.com

A modern smartphone with a battery which lasts more than a week.

Actually my New Year wish is that all gadgets come with a nuclear battery that will last more than the entire lifespan of the gadget and will never need to be recharged. Let's solve this silly battery recharge problem once for all...Please.

A weekly/monthly report of my utility (electricity/gas etc.) usage pattern in my home. For example, we get a monthly utility bill with breakdown of how many KWH etc. was used. But I want to know specifically by rooms. Something like:

    Room | Usage when room occupied | Usage when unoccupied | 

The above will tell me if we are wasting utility for no reason etc.

Restaurant reviews where people could review individual items on the menu.

Some way of easily and reliably tracking what you're eating.

And even better, a prediction system that tracked what you ate and provided menu-level recommendations!

have you seen http://www.foodspotting.com ?

E-book subscription service. Basically Spotify for books: You pay a monthly fee and get access to all the books you want. I don't use the Kindle or buy books through Apple because I hate the idea that because of DRM I'll be forced to always use the same reader. With a monthly subscription that problem is solved.

I'm a student, and I'd love a simple way to manage my income without having to faff around with spreadsheets and formulas (or more advanced finance software.)

I'd love to be able to manage my bank account with it, put a bit away every month and work out how much I have to spend - but in a clean, simple interface.

Have you tried mint (http://mint.com) before?

Furthermore, it's not available for the world atm :)

You can look into open source, free software in the same category. I believe you can find decent one by googling :P

you basically want a money manager, but on a student budget. How much would you be willing to pay for this service per month?

A 3d scanner and 3d printer, both controlled by a phone. I should be able to send whatever I scanned to my friends and have him/her to print it off rightaway(3d fax?).

I want to see the 13" ASUS TAICHI and Padfone 2. Also, AMD ultrathin laptops with good integrated graphics.

i want an armchair, which has one part of an divided keyboard embedded in each armrest, an extended right armrest for my mouse, and a monitor which is(somehow) mounted to the chair but adjustable. i couldn't afford it right now, but i value it at about 1,5-2k

That actually exists but is a lot pricier than your budget I'm afraid. http://www.mwelab.com/index.php/en/products/emperor-1510

I really wish to have a robotic maid at home. That would solve the biggest problem for me!

I would heartily suggest a cleaning service.

This actually solved the largest problem in my marriage. As it turns out we live busy lives, hate cleaning, and hate living with the mess. Once we got a cleaning service, we stopped fighting about cleaning - and since that was pretty much all we fought about - we stopped fighting. Really freaking fantastic.

Some relationship problems really do have simple fixes. And for some of us cleaning services border on magical.

I know...but I don't like some stranger coming to my place...therefore the robot.

find someone you can trust. it's not that hard. start with people who are already trusted by people you know.

roomba is actually pretty good

I already have a Roomba. Many issues. It is not powerful enough. It cannot do stairs. It cannot clean furnitures. It cannot self clean.

I want a tiny tablet with the form factor of an iPad with an active digitizer.

I would absolutely love a retina display monitor.

What size? and how much would you be willing to pay for this?

27" wide screen. I will pay $299 for that.

I see 32" 1920x1080 (1080p) lcd/led tvs seling for ~ $200. Would that not work for you?

No. That resolution is way below Retina display.

I think everyone would be clamoring for one if it was only $299

< 3000$