I obviously did the C-5 thing and here's my 2 cents. I would go with either the C-5 or the C-17 and probably the C-17 between those two depending on your preferences. I like strat-air (C-5/C-17) because the mission is to actually go somewhere...anywhere in the world and drop cargo and troops. Tankers travel the world too but I think generally their mission is to pass the gas and then head home. Therefore you might do a lot of taking off, drilling holes in the sky like TankerDriver described and then landing where you took off from. (You tankers guys keep me honest if thats not accurate). As fro the C-5 they are upgrading them now with glass avionics but they are doing the active duty first so it will probably be several years before they get to the guard and reserves. However, if you get in the Reserves as Dover or Travis they fly the same planes so you'll be flying glass. I agree that one of the nice things about the C-5 is that its huge. The crew comforts are probably the best in the AF. I'm still amazed at what we can load on that plane and how far we can take it. Several times I've gone places like Australia or Jordan and had lines of cars stop while people came out to watch us takeoff. However, that all comes at a cost and the cost is maintenance. The C-5 breaks a LOT. It can be very frustrating to get alerted and spend 4 hours getting ready to takeoff and have to go back to bed or having to divert enroute because something crapped out at cruise. The good side of breaking is that you're often in a place to go see the sites. The C-5 will give you several mini-vacations...whether you want them of not. The AF is pouring a lot of money into C-5s now to get their reliability up (new engines, hydrualic, system, avionics and a ton of other stuff) but it will take several years to get the fleet done.

The C-17 has most of the benefits of the C-5 but it is more reliable and the AF is still buying them. They also do a lot more as far as airdrop, assault landings, and low-levels. So if you like all that then the C-17 or C-130 is the probably the way to go. I'm a pure airland type of guy so the C-5 worked for me. The flip side is that if you plan to be a part-time guy and work another job I hear it can be challenging for the 17 guys to maintain currency for all the things that you may be checked out to do. Hopefully the 17 and 130 guys will chime in and elaborate a little more.

Also dont forget the KC-10. I've always been fond of that plane. I dont know how much but I have seen those guys out flying just cargo so that may be away to get the best of both worlds.

The bottom line is to continue gathering info like you're doing and KNOW WHATS IMPORTANT TO YOU. The location that you live may be the most important thing to you and that could overrule everything mentioned above.

Good luck...