Wow. Didn't expect this much response, to be honest--thanks to you all.
Right now I'm gearing towards a very long term approach with my Roth IRA, going all index funds for the exact reasons Steve mentioned, and I'm not worrying at all about a life insurance policy beyond SGLI. I thankfully have zero debt of any kind, which is a blessing.
I've also considered putting together a CD ladder on top of my savings account reserve to provide me with an even larger safeguard against calamity and to help that money grow while it sits--any thoughts on that? My savings account has a pretty good interest rate, so maybe that doesn't even really make that much sense.
I guess the big motivation for me to start this thread was to see if anyone has had any experience with some of the larger companies out there that offer index mutual funds for minimal fees. I'm thinking along the lines of T. Rowe Price, Janus, Fidelity, and I know I'm forgetting a few others but I can't think of them off the top of my head. Play Devil's advocate with me.
I'm leaning away from USAA because I've not heard good things about their investing arm (I've been a member since I was a freshman in ROTC, and love them to death for banking and insurance) and because they don't have much options I would exercise that I don't already have in the TSP.
I don't know much/anything about several of the companies you've mentioned--how did you find out about them, and what made you decide to go with them? I'm not really interested in selling as much as I am in buying and holding long-term, so would TD Waterhouse / Scottrade be anything I should look into? And don't brokers just try and sell you the stuff they've got to get rid of?
Thanks again for all the input!