For what you ar doing the K8N would be your best bet. The K8N supports 3 gig of memory where as the NF8 only supports 2. The K8N has 8 channel audio as opposed to 6. The Asus board is a better board in my opion. Easy to work with and if you want to overclock you can do so pretty easily if you wish.
says your board is a Socket 754 for AMD Athlon 64, Sempron. So I did a query on newegg.com for 754 socketed CPU's. This doesn't nessacaraly mean that this is all you can get but it does have quite a list for you to choose from.
The "slowest" chip the boards support ( will) is the sempron s754 2600+. The fastest chip the board will support is the A64 3700+
The main diferences between the two Asus boards is the extra sata on the E, and that the non-deluxe supports the nvidia firewall.