I try to buy as many games I can but with limited income of course it's hard to get all the great games that come out. Some PC games are very hard to find also which I personally don't see a problem trading but I can understand how some people might...Patching PC games is pretty much the same as patching PSX games to get past protection however.
I'd rather rent new games then download them as far as PS2 goes. If I know I won't buy it at least this way I'm somewhat supporting the developers :lol. If I intend to buy a game but can't buy it right away I consider downloading it depending on how long I gotta wait, or just renting it.
I do like having actual boxes and books for a lot of games, purely for collection value. If you really think about it though even buying new used games when you could buy the original hurts the developer. There's some I make sure to grab a sealed copy of just because I want the company to do well. Nippon Ichi is the best example I can think of, there are others of course.
To get back on topic last games I purchased were Lunar Dragon Song and before that Skies of Arcadia, Fatal Frame 1(ps2) and the last Resident Evil game for my collection, Resident Evil 2 for the game.com handheld system.