Need advice, please

I would go with the 24-105 on the 5d. Keep your fifty close to hand. I bought a tripod with pistolgrip head and a monopod in preperation for my first wedding and haven't used either. I would practice with the flash Lori! There is a really good thread here from a couple of days age titled FEC? Oh! And yes, definately, at least 4gb

And good luck

One more thing, make sure that you put a FRESH formatted CF card in your camera (minimum 2gb) prefer 4 GB right before the ceremony starts. You DO NOT want to have to change cards during the ceremony. It will fluster you since it's your first wedding and don't forget when you fill one up and hand it to your friend and he hands you the other one, it's not as simple as snapping it in and continuing to shoot. You have to reformat the card and then you can shoot. This takes valuable time. So you want a empty card ready at the beginning of the ceremony. Good luck.

Gotta tell the pro's here, I always had great respect for you, but after shooting the wedding it has increased 100%. Let's just say, I got a few good shots, but have a long way to go before I'll ever agree to do that "please help us out" favor for anyone ever again. Lighting was horrible, and my ISO wasn't set high enough. I feel like a total failure! At least there will be a few nice shots for them, though, which is better than nothing...

A few shots are better than NO SHOTS! You did this for free for your friends... you're probably being a bit overly critical on yourself too.
So good on you for doing that for them - and yes maybe a lesson learned on the way.
You;re still here to tell the tale!