Well, Dread, as you know - no decision is easy. Our surgeon feels that we'll take the next step only if needed and he's also 50-80% confident we won't have to face a return in our lifetime. If it does rise, in his opinion, it won't reach drastic measures within each six-month testing period. I made him swear that it wouldn't ;-) !!!
With an undetectable PSA, those little remaining cells may never, ever resurface. In that case - for us, anyway - we have avoided the hormone/radiation therapies that we chose to avoid in the first place - and for all the obvious reasons many have outlined here.
I will say that if our PSA had been anything but undetectable, we would be looking at other options.
Husband age 65
PSA on 5/1/06: 4.2 (had doubled in 13 mos. and rising monthly)
DaVinci Surgery 8/2/06
T2a (at biopsy)
T4c (at pathology) w/cancer cell leakage into fatty tissue
Post-Surgical PSA on 10/3/06 - undetectable!
Update: 11/1/06 - perhaps bladder neck involvement; 30%-50% chance of recurrence
Future: PSA tests twice-yearly for now