even though any current cpu is overkill for websurfing, it is still wise to buy something that exceeds your current needs... as the OP said, he wants to keep his PC for a few years...
but it's also true that his current A64 3200 is still good enough... so it may be possible, if he had trouble with this CPU, to help him fix that... with the spec of his PC and a description of the problem, it might be solved without even spending one cent. moreover, changing CPU is no use if the problem comes from software, or from another part of the PC