Tony Blauer heads a forum called Q&A: Mental Edge off of the Underground forum at
www.mixedmartialarts.com. (you may want to check the archives of posts before you post)
Tony is an awesome, down to earth guy with some pretty profound ideas about combat and mindset in general.
To be honest with you, recommending a particular martial art would be like recommending a brand of handgun and caliber choice. Your best bet is to check out some schools in your area, find out where you feel the most comfortable and start training. The more realistic the training and the more sparring you do, the more you will get out of each session.
As fubsy alluded to, one of the best submissions is conditioning. If you aren't properly conditioned, you are not going to get very far.
If you are interested in HTH weapons, there are people with far far more experience than I but I have heard good things from arts like Arnis/Kali or Dog Brothers style stickfighting. The good thing about learning how to fight with a stick is that almost anything from a rolled up newspaper, umbrella or some weird thing you might find in an alley could turn into at least a good distraction and at best a formidable weapon.
In any event, the people on
www.mixedmartialarts.com have been probably the best resource I can find online in the last two years or so. If you have questions on anything from a particular technique (submission or strike) to where to find a good place to train in your area to which martial art would benefit you the most, they would probably be the best help as there is a good amount of people with a LOT of knowledge regarding martial arts.
Good luck with your studies!