I know this thread has been dead for over 2 years but thought I would update it.
I was a little late to HP's 3.0 update, but finally found some discs this past weekend. The server restore went good, but my office PC couldn't find the WHS. I anxiously just let it sit for 2-3 hours and it did eventually find it... thank goodness.
3.0 is more demanding and decided it was time to look for a CPU upgrade. I read several threads on the SLAY7 sSpec e5200 being a plug and play swap. It was to an extent. I sucessfully swapped in a e5200 after work today, but speed step was holing it back to a 6x multiplier. I had to modify the BIOS in Windows (remember the ex485 is headless) and even then it didn't take the speed step and PECI change. In the end I took the ex485 apart a second time and pulled the CMOS battery. Now speed step works as advertised.
I ran OCCT for 10 minutes and the e5200 only showed 62c . Not bad. Although the Home Server Console shows it around 62c at idle (it was ~59c with the Celeron 440).
I'm debating going WHS 2011 on this box now. I would lose some features like the drive extender, but would like to have the latest and greatest. I know the e5200 could handle it too.