It's hard to go back to an older build thread and use those choices for today. PSA wasn't talked about as much then for example. I'd say look at Agent Tikki's recent AR-15 Primer then start thinking about your uses and a reasonable budget. I agree with Purehavoc that PSA is a great choice, and that it makes sense to buy a complete factory upper instead of putting one together. And I'd definitely go with PSA over Del-Ton.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek