I haven't purchased Visa gift cards, but I frequently use my Hilton HHonors AMEX card to buy store gift cards (Starbucks, Lowes, Target, etc.) at the grocery store to get 6 pts/$ vs. 3 pts. at the stores themselves. For my Citi cards, I will charge things like my electric bill, cable bill, EZ tag for tolls, etc.

I've read in various places that you need to be careful about fees associated with the Visa gift cards, but to be honest I haven't looked at it carefully.