Here's my list of what I will buy from people:

Sega Master System:
Global Defense (B)(I)
Teddy Boy Card (I)
Walter Peyton Football (B)(I)

Genesis: Manual and Boxes Need List
Alien Storm (B)(I)
Bonanza Brothers (I)
Elemental Master (B)(I)
F-22 Interceptor (B)(I)
The Great Circus Mystery starring Mickey & Minnie (B)(I)
Marble Madness (B)(I)
Ms. Pac-Man (B)(I)
Road Rash (B)(I)
Sonic and Knuckles (I)
Sonic Spinball (B)
Sonic the Hedgehog - NOT FOR RESALE (I)
Sonic the Hedgehog 2 - NOT FOR RESALE (I)
Sports Talk Baseball (B)(I)
Sword of Sodan (B)(I)
Technocop (I)
Vectorman (B)(I)

Genesis Hardware:
I need another orphaned Sight for my Menacer.

I don't really care if the manual says NOT FOR RESALE, but it never hurts to try for uniformity :-)