Try these guys if you already haven't:
http://www.cessna150-152.com/
Everything you could ever need on the 150/152. 20 bucks to access all info. I'm a closet 150/152 fan and plan on buying one in about a year or so (waiting to see what happens to my company first). I prefer a 150 (68/69, 73/74 are my pref for model years) with just one radio/mode C and the basic instruments. This keeps it light so your useful load is still "useful".
The 152 (all model years) have atleast 2 inches more cabin width than the 150. This is big if your going to use it for instruction. The 152 GW is 1670 compared to the 1600 in the 150. Now most 152 empty weights are alittle more than the 150 but if you keep the 152 simple (basic instruments, one radio/vor and Mode C) and don't junk it up with gps/lorans or extra radios (not needed in a 150/152) than the 152 will have alittle extra UL. The EW on a 150 should not be more than 1100 pounds. If this is the case than its either got heavy radios or too much junk in it. 1000 to 1050 is a good 150 EW. For a 152 look for an EW around 50 to 70 puonds more.
Another thing in the 152 is that your airspeed indicator will be in knots. Not a biggie but if your students move on to other equipment like an archer/arrow for inst/commercial stuff it will also be in knots.
All in all if your going to use it for instruction I'd recommend a 152 because of the extra room and UL (not much on both accounts but every bit helps). That coupled with the 2400 TBO.
If you just want one for yourself I'd say 150.
As for me I'm on the hunt for a 73/74 or 68/69 150 with a mid time engine, simple panel and low empty weight (low EW also equals better perf., yes I know it's a 150, try not to laugh) for about 16000-20000.
Good Luck, let me know how the search goes.