When I got my ps3 I only had a 68cm standard def tv and it was hooked up through an AV cable. While it looked ok it didn't look as good as I thought it would be. So I decided to go for it and went and got myself a nice 101cm Samsung 1080p LCD tv and HDMI cable and the difference was huge. Reason is that with the ps3 and 360 games run natively at 720p or higher so you can't really take advantage until you get a hi def tv.
So in your case if you are going to wait a year or more it's ok because by that time hi def tv's will get much more affordable. Besides games I got my ps3 and new tv for movies and I gotta say I got my money's worth because the ps3 comes with a bluray drive which means I can watch high definition movies without having to spend extra money on hardware like you would have to with the 360.
Besides all this I have figured out how to stream movies and music from my computer to my ps3 so when I buy a new sound system I will have a nice little theatre in my little room hehe. So far my experience has been nothing but fun :)
