Streetfighter IV sounds like a good buy.

I bought N.O.V.A. today; the players on multiplayer were few (prob cause it's Sunday) and were satisfactory; easy kills.
The campaign is nice, one of the few real games in the app store that HAS a storyline (a real one).
It's a decent gun game; good buy IMO.

Monopoly: Here & Now I felt was a good buy as well, as the sale price is $2.99 at the time I'm posting this.

Besides Chaos Rings, are there any good turn based games in the app store atm?