I don't know what airlines would be most convenient for you, but as far as a credit card, I like the Starwood American Express best. The points you get with it can be converted back to airline points for many carriers and for me, I get 25,000 AA points for 20,000 Starwood points. I live near Dallas so I use AA for most of my trips, including Japan and Europe.

I have only recently begun to lurk here and I haven't had the time to look for special limited time offers from various credit card companies. I am less inclined to do that anyway. I prefer a good, long term card whose "good deal" is not going to expire in 90 days. It seems the Starwood AmEx is well regarded for that in these forums.