Wait nothing! Go for the AMD 64 3000+. It's first rate and very affordable. It will SMOKE the 2.6. For that matter, it keeps up with Intels 3.2 on some of the bench marks.
As for as a mobo, go for the MSI or the ASUS. From what I've read, the MSI is a little more stable than ASUS, which I found surprising. My cousin just slapped a 3000+ w/ MSI together and damn, it's the fastest rig I've ever seen.
Plus, if you go with the 3000+, you can load Windows 64 in a few months. Welcome to a whole new experience!