Playstation all the way! Whether PSX or PS2, this is definitely, IMO, the best system out there. It has the widest selection of games, in all genres, as well as the best quality games of all consoles. Square and Konami... kingpins of the market who choose Sony.
Xbox doesn't have enough good games to sustain it (and its uh... big)
PC... you're limited in screen size and controller comfort... and the variety of games cant compare to the PSX+2.
The gamecube has cornered the market in kiddie games and is now having trouble breaking out of that stigma... it even looks kiddie-like.... like a piece of the background scenery you'd find in Mario or something. Although... it does score bonus points in the aray of colors that the console comes in... PINK, YELLOW, PURPLE! But, if its only benefit lies in the asthetics of the machine, then it might as well be a Mac. (and the limited edition PS2 systems are now available in a variety of really awesome colors... not that classic black isn't always hot)
As for RPGs.... the gamecube may yet get a boost in popularity.... it is to my grave displeasure that after Final Fantasy XII, Square has given the word for the series to be available exclusively for Gamecube. To test the waters, they are releasing FF Chrystal Chronicles for gamecube, which actually looks pretty awesome.... which angers me b/c i dont want to get a gamecube... but if they keep up this trend, i may end up with one.
But .hack and Xenosaga are out on PS2 right now, and I hear they are awesome, and I know I plan on getting FFX-2 in May b/c FFX was my favorite game.
Basically, to wrap up and keep this from totally going off topic.... what I'm trying to say is that nothing more than the games make the system... no matter how pathetic the graphics are, everyone remembers Sonic from the Genesis with a fond heart..... it was a good game.... most of Genesis' games were..... and regardless of the graphics, any hardcore gamer will agree that the games make the system.... you'll buy a system for the games, not the brand.