I know this has been covered 1000 times, but I would appreciate your help choosing a card. My profile:

No fee Visa/MC not Amex
Pay balance monthly
Delta Silver but only at about 17k so far in 2007
SWA -- 7-8 flights per year
HH Silver (7 stays so far in 2007)
Marriot Silver (7 stays so far in 2007)
Avis about 10 rentals per year
Great credit
Charge about $3,000 monthly
Don't have a preference as to miles or cash back

Thanks for your help.