Highly recommend this:
http://www.amazon.com/Metro-Vacuum-E...rds=air+vacuum
It was actually only like $40 when I picked it up, but yeah, it's amazing and still worth the higher price. Similar to you I was sick of going through canned air, plus they're just a pain to deal with (losing pressure too quickly from continuous use, have to be used at a specific angle, etc) and overpriced for how long they last. I clean out my PC pretty often and had extra cash-back points at the time, so I found it pretty easy to justify spending a bit of money on this.
I was worried about the pressure, but this thing actually pushes even more air than the compressed cans. It's pretty ridiculous; it literally blasts dust and shit across the room (use it outside lol). It's loud, but good; especially in combination with the tools it comes with.
It's so good I constantly have 3-4 friends/co-workers/family that are lined up to borrow it for cleaning out everything from PCs/keyboards/laptops, to air conditioners/vents/fans, to cars, to sidewalks, etc... So yeah, it comes in handy for a lot of different things and works very well.
EDIT: The amazon reviews do it justice pretty well, and the first review has a video of it in action.