If your going for bike worth and not to motor it's a little different-
After a lot of time on Ebay,and a life around bikes, the things most prized now are vintage 70's road bikes and frames- with alloy cranks- not too exotic- things got a lot more exotic through the '80s and the quantities are smaller and not so universal
I'd look a lot for alloy- cranks, brakes wheel rims in good shape, nice lugged road frames keep their worth- exotic suspensions of later bikes keep changing-
Bikes for recreation and transportation are best with 700 c wheels-
off road is off road- it became a trend in the early '80s and off road is big- but the manufacturing and marketing trends went too much in that direction for the practical transportation aspects now- I put a lot of Specialized mountain bikes together in the early '80s and I knew they'd never leave the pavenment.
The manufacturers shot themselves in the foot getting away from the lugged road frame by catering to road racers exotic tastes and mountain bike consumer trend. The kid wanted a mountain bike from Target.
I'm sitting in Bloomington- lugged road frames, even heavier old Schwinn pig iron ten speeds are popular- "fixie" has been big, but I think topped out- here it's a little hilly to ride fixies all the time. Campagnolo Record and Super Record components from the 70's and early 80's are still the most prized and get the most money on ebay- may not see that at auction. They shoulda stopped there, or start making it again.
I like annodized alloy- sharp and popular- makes the bikes attractive as well as practical.
VP-747 Bear cage trap BMX alloy pedals 9/16" - RED ANO - eBay (item 200517176453 end time Nov-06-10 13:46:21 PDT)
I like these bear trap pedals for commuting and on my builds- they are light and attractive, AND the wide pedal really seems to give a certain mechanical advantage when not strapped in and ankling otherwise- it's a longer fulcrum you can put your weight further over on the downstroke- there's a whiole bunch on ebay in both 1/2" and 9/16".