If high-demand multi-tasking is not planned, would a 2.6 single or 2.2 dual core be better?

Low-demand equates to whichever cost less to you.

for low-demand applications, a single core cpu is alright as long as u ve sufficient ram (i myself is using a P4 2.4GHz with 1GB on XP, everything is pretty smooth)

however, having a dual core system is future proof, as many programs and games are going dual core as well, the new ones are written to take advantage of multi-core cpu, and will run faster than single core systems

for the 2 cpu that u ve mentioned, i believe they are Athlon64 4xxx+ and Athlon64x2 4xxx+, i wouldn't say AMD is crap, but Intel has the edge in the current cpu market... if u re short on budget, then going for AMD is fine, anything that is 5000+ or higher are still pretty good, but i suggest that u get a Intel Core 2 Duo system, cuz u get more for the money that u pay

the 2.2 dual core will still be a lot faster, but let me take this opportunity to pimp intel to you. amd is crap and anyone who knows anything about anything will tell you the same thing. :P