If ur building a new gaming machine, u should go for an Athlon 64 venice/san diego. About XPs, i believe Bartons, as i do believe they are pretty good OCers.
you will not find as pentium that is comparable in price or games performance to an AMD. go with the athlon64. 3200+ and 3400+ are pretty cheap and effective.
Cool, I am just upgrading the CPU. Eventually I will do a major upgrade and get a new board and a 64 CPU but for now I need to stick with a socket A CPU.