Just stay with one. If you travel for business, have your travel agent nominate you on that airline for basic elite status. You fly 1-2 times per month. YOu're not an almost FF, you are one. You can spend the money on UA to get E+, but then you're stuck with UA and your chances of ever getting upgraded to the front are really minimal. Plus, you're then stuck flying US Air if United isn't a good rate. I'd go with Continental. You get good service, a stable airline, upgraded with status from time to time and you can use NWA, Alaskan and Delta.