Welcome to FT!
Are those mileage totals EQM or RDM?
The first thing to realize is that miles are like free money that airlines give you in return for your business. Treat them as such. Then, define what you want to do with the miles you earn. Do you want to upgrade your paid flights, or take trips to Oz or Europe for free? Make a plan for your miles.
Most people think that trying to concentrate your flying on one carrier as much as possible is the way to go. However, if you are at the mercy of the government travel ofiice, that's hard to do. I would pick one of your SkyTeam programs to stay with (which one will depend on who you fly the most, I guess,) and keep AA as well. Many people think that flying on US Air while crediting the miles to UA is a good way to go - but it's up to you. As far as Southwest: (WN) I guess it's inevitable that you will fly on WN a lot from LAS, much in the same way that you will fly US/HP. I personally don't think the WN program is worth much, since all that domestic flying in coach will eventually get you...another free domestic flight in coach. At least the big airlines go overseas, and your miles can get you into the premiuim cabins.

Just pick a program from all three of the major alliances (Star, oneWorld and SkyTeam) so you always have somewhere to credit a flight. I would try to avoid WN, jetBlue (B6), Frontier (F9), ATA, etc, as their programs are not affiliated with the bigger airlines. But it's up to you. Have fun, keep asking questions when you need to!