Graphics are part of the experience, and can greatly compliment gameplay - but it doesn't work the other way round. Good graphics can't save bad gameplay.
I found Test Drive Unlimited to be a great game, but marred by the bad graphics - not marred enough to stop me putting hundreds of hours into it! Battlefield 2 also didn't have AMAZING graphics, but even today I still love to play it regularly, and same for Rainbow Six Vegas 1&2.
Then, there are games with great graphics, but which have bad gameplay... Gran Turismo (4, 5 Prologue) is brought to mind here. People can say it's a "realistic" simulator (It isn't, by the way. I drive in real life and it is NOTHING like the real thing), but it's just not fun at all and its only purpose is to look (sort of) pretty and to make your ego bigger. Army of Two had ok graphics but I felt like a robot because the gameplay was so trivial and mundane. Turok had ok graphics too, but WOEFUL gameplay.
Then you have your CoD 4 and 6s. Bad graphics, bad gameplay and shunning us PC gamers. Makes you feel that the game is saying to you "You couldn't possibly be good enough, so I'll make you feel and look like you are".
Wow, I just dumped my opinion here didn't I... Also, someone mentioned Crysis - I loved it. If you aren't sour about not being able to run it on very high and wait to afford the PC to do so, then it's an incredible game with great stealth and shooter gameplay and graphics that will make you so immersed in the experience that you feel like you're there.
So in the end, yes, I do need graphics - but only in certain games, and in said games only enough to make them immersive. Also I play PC, 360, Wii and PS3.