well, just my 2 cents.
I would need to have some confidence in the quality of a PSU that was 4-5 years old before putting it in a new rig.
There have been some significant improvements in quality , both efficiency and regulation in the last few years.
Also, the continued move to 12 V predominance.
So, while you won't need a huge amount of wattage, clean power is always important to maintaining electronics.
I would look for sales on super-flower gold and platinum units.
Rosewill CAPSTONE Series CAPSTONE-550 550W Continuous @ 50°C, 80 PLUS GOLD Certified, Single +12V Rail, ATX12V v2.31 / EPS12V v2.92, SLI Ready, CrossFire Ready, Active - PFC Power Supply
is often on sale for $60 ($80 today not on sale.)
Not a fan of OCZ. have some OK models, but also some that I would steer away from...mixed together, it is hard to tell on grade from the next.
If you are will to pay $100, then this is probably the best on the market (quality/value)
KINGWIN Absolute Platinum Series AP-550 550W ATX 12V v2.2, EPS 12V v2.91 and SSI EPS 12V v2.92 SLI Ready CrossFire Ready 80 PLUS PLATINUM Certified Active PFC Power Supply