Need soema advise on new PC

Ok my original rig was:

AMD 3800+ duel core cpu
2 gb RAM
ATI x1900
300GB HD

~:)

However,

Some one told me a cheap AMD 64 will do and not only will thsis top me spending £900 but also maby let me spend the money on something else.

Also what would be the difference between each?

Tahnks

Tib

Is it me or is there some info missing in your post?

Argh probably.

It's been a long day. ~:(

Will get the rest of the info in the morning when I am mor awake. ~:)