Chair Force ... lol!!
On a serious note. Ill throw out some opinions in as unbiased a way as possible (coming from a Soldier)... Ive had quite abit of exposure to the different services in many joint operations and I have had members of each branch work directly for me in combat operations during the "surge" of 2006-2008.
Air Force- Air Force personnel that impressed me the most were the old school folks that were retiring soon and hated what their branch had become. All the other folks (including the Security Forces guys I had working for me for 6 months at a time in Iraq) were very unimpressive. Disciplinary problems and failure to understand that the mission comes first (before Xbox and Salsa Night at the MWR) were the major issues. This is not to say that the whole Air Force is messed up. All my interactions have led me to feel that it is not a disciplined and structured instition or fighting machine like the other branches. The Air Force of today seems to be quite a bit different than the Air Force of old. They have changed their philosophy and approach to dealing with service members to that of a corporation. Which is that everyone deserves to be treated very very well, don't stress them out much and they won't leave the service. This is a good way to think in my opinion except that in an instition that is supposed to be highly discplined and able to operate under stress - the two don't equal out from what I have seen.
Marines- Outstanding professionals for the most part. I have conflicting opinions about the Corps due to my experience with them in Western Iraq during the first years of the Iraq war. I was highly unimpressed by their 'ego' which got Marines killed. The ego prevented the Marine company level leadership from listening to the Army 'pukes' that had been on ground in the fight for months and months. I carried quite a few young kids on stetchers because of this and I have always had heart burn because of it. On the other hand, since then I have had three different Marines work with me. A little hard headed but had absolutely no problems with completing their duty before thinking of themselves. I highly respect the Marines I have been around in the past two deployments and their actions contributed greatly to the mission and .... well ... theyre hard asses and I like that.
Navy- I lived with a squid for a while and had a Navy Chief work on my team for almost 9 months last deployment. Super guys. Well trained and mission dedicated. I really felt that these folks had an idea of what was going on and were ready to make sure their weight was pulled. Always offering good solutions to problems and ready to work.
Army- Pick the right field to work in. The Army is a giant machine filled with people from all ends of the spectrum in terms of intelligence and personality. I consistantly meet people I think should have been placed in a microwave as a child but then I meet others who can move mountains in their sleep. A smart, self-motivated person can make a strong career in the Army with ease. The downside is that we carry the biggest load of all the services for land based combat operations. The other services don't even come close in that catagory. We typically deploy every other year for 12-18 months. We don't get the Air Force "perks" of nice living arrangements, short deployments and not being called 'maggots'.
My overall opinion is don't pick a service because of the perks. It's not worth having or doing if it isn't hard on you. Physical and emotional stress bring out the salt in you and pound for pound I think the Marine Corps or Army are the places to be.
I hope this helps and by all means... no matter what you pick.. its a nobel choice and you will be part of a very small and proud group of U.S. citizens that carry the responsibility of protecting a nation. And whether you are sitting behind a desk answering phones and taking memos for a flight crew, refueling water craft or out wading through trash filled streets in Baghdad collecting intel that brings down a terrorist cell; you are doing your part.