Sikpupi,
Both the PS2 and the XBox have their Pros and Cons.
The major complaint about the PS2 is from programmers. The PS2 is one of the hardest consoles to program for.
The major complaint about the XBox is the lack of game titles. (Even though it is easier to program for.)
Your best bet is finding out which games your kids want to play, (since I am guessing you are going to give them some games along with the console), and that should help decide which one to get.
Take Care,
Richard