Any comments on this?

I have a x86-64 system with one Xeon(TM) CPU 3.00GHz running CentOS 4
with 2.6.9-34.0.1.ELsmp (hyperthreading) as a production PostgreSQL 8.x
database. No probs so far.

 
Pretty much same setup here and no problems, always have HT enabled and never really had any problems. Mileage may vary depending on what you run on it basically as to whether its a good/bad thing in terms of performance.