If the E8400 Wolfdale is out of stock take a look at the E6750 Conroe (2.66 Gb). Great bang for the buck and from what I've read it's easily over-clockable to over 3 Gb on stock cooling. I just got one and it's great (but I haven't OC'd it... no need to).
Also check the performance specs at Tomshardware. IIRC the 6750 is almost as fast as the 3 gb Conroe that you're looking at for almost $100 less.