wich one of those pc's ?

hey
i was looking around on newegg, for a pc around the 800$-1000$
they look almost the same
but not completly
wich one is the best?
i don't know much of them.
I only want a cpu to be 64 bits and 3.4 ghz or more ...
http://www.newegg.com/Product/Produc...82E16883107165
http://www.newegg.com/Product/Produc...82E16883103022
http://www.newegg.com/Product/Produc...82E16883107167
http://www.newegg.com/Product/Produc...82E16883107168

i just want to becapable to do several thigs at the same time, like, cs, photoshop, dreamweaver, firefox with 10 tabs, msn and few other things maybe also burning cd's at same time ?
i'm doing everyting on same time on this computer, exept for the cd, but isn't too fast
Thanks !