I'm not a big TKD practitioner, and I am in fact not really active in TKD currently. I trained TKD from age 7-18 (WTF style) and every now and then I get the gear on and spar.
Here is what I got out of it....
1. Discipline; Being that I was young when I started especially, I can attest that if your TKD instructor is good and hard on you, you will develop the discipline to do just about anything.
2. Physical "tenacity." The TKD school I came from helped me to become physically "tough." This was mostly because of my instructor. He was a World Champion Kickboxer as well as a TKD master, and he put an extreme amount of emphasis on body conditioning. Technically speaking, we weren't nearly as advanced as the Filipino stuff that I focus on now. But physically speaking, we were very tough. We used to spend hours and hours on basics. Serious calistetics and body conditioning was included in every class. I used to have to do all kinds of crazy breaks also; 2 board spinning heel speed breaks with one guy on another persons shoulder; flying side kicks on a wobbley deck over water at a Marina, jumping split kicks, 10 brick breaks w/ palm when I was only 16 years old, etc. The list goes on; and although I'd most likely never use something like a jumping split kick (or half of the breaking techniques) in a fight, the fact is this caused me to have to push the potential of my mind and body beyond my limits. This aspect definatily applies to life or death situations. Plus, we used to fight all the time. Kickboxing, boxing, and open tournament style, not olympic style. With our tournament style fighting we would go medium to full contact; sometimes bare knuckle (which was rare and against the permission of the head instructor; because we allowed head shots, and it usually resulted in a blood-bath. I would not recommend this today!). Although we were not very technically advanced, and we were primarily a blocking and striking art (no joint locks, or ground work), the sheer tenacity, willpower, diversity, and overall "toughness" of some of the students that came out of my TKD school would allow them to beat people who had better, more advanced technical abilities if there ever was a fight.
It was because of my TKD school that I was able to easily do my share of NHB fighting (when I learned some ground fighting concepts), and other things; I had the physical tenacity to do so.
3. Distance and timing. TKD allowed me to develop an extreme sense of distance and timing that I don't think I would have gotten from my Filipino Martial Arts alone. With this sensativity of distance and timing, however, I am able to translate this into my current FMA training fairly well.
Through my personal TKD experience, this is where TKD has benafited me.
I do like the fancy kicks. Breaking is loads of fun (had breaking week this past week). And I'm a forms geek. I like to do a well-done form. I like to make my techniques "snap" and be sharp 
My fav TKD form is Tae geuk sa jang (4). 
I was just thinking about the WTF for some reason, and I slipped up on my typing.
