What I consider to be a good investment is a decent microscope. I use a
B&L Stereozoom 3 with 10x eyepieces, so I get 7.5x to 25x. Plenty good
for surface mount components. You can always add 20x eyepieces if you
need more magnification. The illuminators are about $20 surplus, but if
I were starting out from scratch, I'd rig up some sort of white led
illuminator.

Second best is a Luxo lamp. Surplus prices about $300 and maybe $20. I
haven't seen used Luxos in some time, probably because they just aren't
powerful enough.

This is the type of Luxo used in electronics assembly
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=42884&item=7516115 156&rd=1&ssPageName=WDVW

This is a typical B&L stereozoom set up with a heavy base and arm so
you can position it over your board, gear, etc.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48740&item=7516441 151&rd=1

I don't think I'd every buy these kind of items on ebay. You really
need to inspect the glass on a luxo and the focus action on the
microscope.