For $20 extra I'd say go with the E4500... w/ only 1MB of shared L2 cache, the E21xx series are not the best choice for gaming and applications that see performance increases from extra cache. Only 5-10% difference, but for $20 its worth it IMO.
I'm not sure what prices you are looking at, but if you want to save money this E2180 for $49.99 AR is the best deal right now:
http://www.tigerdirect.com/app...BGOOCPU1&CMP=KNC-GOOGL
Note that it is an OEM CPU, so you need your own HSF, but if you will be overclocking you'd want to replace the stock cooler anyway.
E4500 will still be better but it costs twice as much.
I'd reconsider on that motherboard though. 680i is an outdated chipset and not the best for a new setup, especially if you plan to go 45nm one day. You'd be better off with a P35 motherboard such as the IP35-e, which can be found at Newegg for $70 AR.