So yeah, be creative when determining the value of an item. Some items look pretty bad when we consider our own character, but another play-style might consider it "best in slot."
Here are some things that aren't "cookie cutter" stats but particular classes find them very valuable. Please add your own ideas!
Follower amulets with magic find - THESE SELL FOR A LOT. DO NOT SALVAGE UNTIL YOU HAVE COMAPRED TO OTHER SIMILAR ITEMS ON THE AH.
Witch Doctor items with pickup radius - Witch doctors use a passive called "Grave Injustice," the radius of which depends on your pickup radius. If you find a piece of gear that is otherwise pretty good, but has pickup radius, do NOT discount the value of pickupradius as a junk stat. Witch doctors covet it.
Blue rings/ammies with life on hit + magic find/gold find/all resists - Last night, the most expensive thing I ended up selling was a blue amulet with 300 life on hit and 60 or something all resists. 1.5 million. I was about to salvage it before I looked at its stats.
ANY item with ~17+ MF: Everyone wants to have a magic find gear. If you have an item with decent stats and ~17% magic find, keep it! If you have an item with 17-20% magic find KEEP IT. Even if its other stats are pretty crappy. Now, if it has otherwise GOOD stats and 17-20% magic find, the thing will sell for millions. ANY item with 20% MF will sell for a decent amount. Some people simple MF switch and therefore don't even care about the other stats
Weapons with two of the following: life on hit, crit damage, socket - This is probably obvious to most of you, but those are basically the stats people look for in weapons. Getting one with main stat and vit is obviously nice, but weapons are unique in HOW MUCH crit damage you can socket into it/roll, and the same goes for life on hit. I sold a 700 something dps one hander (not much damage) with 500 life on hit, a socket, and 70% crit damage for 10 million. In retrospect, I probably got ripped off (it sold quick). Now, I got lucky and had all three of those stats, but you can see that the "dps" stat isn't the end all be all stat for weapons as some people make them out to be.
Helms with MF AND a socket: These sell FOR QUITE A BIT. If you can find a helm with ~15% MF AND a socket, then you can socket a topaz for a total of 30%+ MF. Same goes for amulets with 30%+ MF (even if it's blue and doesn't have much else). I can't give a good price atm, but check auction house and you'll see what I'm saying.
Shields with high block chance - Should sound obvious, but to many people, block chance is ALL that matters (at least, it's the first thing they look at, and without a high block chance, they won't even consider everything else). If you roll a high level shield with +block%, hold on to it:) A sacred shield with ~24-30% block rate can get HUGE amounts if its other stats are even just mediocre:)
There are many others, but I read a post today of someone claiming to have NEVER found anything worth 300k+ in his 100 hours of playing. I find this very difficult to believe. If anyone has other ideas, please post them below and I'll edit them into my comment:)