interactive ads rocks. I'm planning to make a 120x60 minesweeper and a 120x60 slot machine to promote my games.
how about this banner:
http://www.adultwebmasterrevenue.com ,
It has only 32K.(It's not interractive). Admit it, Flash banners are more eyecatching than any .gif ones, and if you're a good flasher you can optimize them, so the size problem will dissapear.