Yeah, I wouldn't want to miss either one. I don't know the full card for PRIDE's 7/2 show (I think it's 7/1 in Japan I guess 7/2 is the U.S. PPV date?) so I can't say. But their GP quarterfinals are sick as hell. If they put even one more decent non-tourney match I'd probably say get the PRIDE show if you can only get one. Aside from Shamrock-Ortiz nostalgia bout and the sure-thing in the main event (come on with it debaters) of Arlovski beating Sylvia in one round, UFC 61 doesn't have much.
Oh wait, 61 also has Stevenson/Yves also and Mir's return. Shit, I don't know bro. Go recycle some cans or something, dig around in your couch cushins and try and get both. That's a tough ass decision.
Just tell your boys the chip in so you can get both. In reality ther only is one fight even worth watchin in 61. Best bet is to watch Pride way better for your buck.