XP is the best OS microsoft ever made

But sadly the updates/support will end in April 2014, but still doesnt make any difference to me
If 7/8 is smooth in your PC, XP will be even faster
XP minimum requesit is 128mb Ram and 7/8 is 1Gb
You can only use 32 bits versions (64 bits versions are unstable and not recommended), which means it only recognizes up to 3,5 Gb Ram, but its enought for me, since I "only" have 4Gb on my PC
The only feature I miss on XP is the search bar on the explorer, but Windows Search 4.0 solves this problem