Sparky,
Just a thought---
If durability is a concern, I just installed 120 V. Red Dot Site Lites. They use med. base bulbs (A15, R20,etc) and seem very well made. The downside is the 12" burial depth.
However, voltage drop was a big concern in my case. (I used 500' of 12-2 UF) Low voltage lighting at those lengths would have been too complicated to try to have uniform brightness. Also, I needed more than 1000 watts total, so I would of needed 2 transformers. Remember that for a given wattage, low voltage draws 10 x the current and therefore a proportionally higher voltage drop. When starting with 12 volts, that doesn't leave a lot of room. If you go 120, remember rocks & roots!!

[This message has been edited by Redsy (edited 06-06-2001).]