Yes, I have 768 megs of ram and it does make a difference. I use newsbin and that thing spools a lot of newsgroups. The text files can become very large and require a lot more than 512 MB of ram. Otherwise, virtual memory has to be increased, resulting in slower memory access.
I say, go for it. You can go for 1 GIG if you'd like, but I think 768 is fine.