CPU Upgrade Question - ASUS P5B Deluxe

I haven’t kept up with what’s going on with front-side bus stuff, so my question to the hive-mind:

What’s the best Intel processor I can get for my ASUS P5B Deluxe motherboard?

Specs here - http://www.newegg.com/Product/Product.aspx?Item=N82E16813131045&Tpk=Asus%2BP5B%2BDeluxe

I’d prefer to not have to buy a new motherboard and processor to do an upgrade.

Currently I have an E6600 2.4Ghz Core 2 Duo in there

The E8400 is probably your best bang for the buck right now, among the dual cores (I’m not as familiar with quad core options yet). Otherwise, anything in the LGA 775 category should work.

Supports 1333MHz FSB CPUs with latest (beta) BIOS

I upgraded from e6400 to q9300 in april. Funny thing is that at the time there was no BIOS released by asus that would support q9300. After some searching found a forum post where some guy who was in same situation talked how he tried a beta bios from dec 2007 and it worked for him. Now it boots with a warning message but everything has worked fine since then, I havent bothered to look for the right bios.