I'd feel totally comfortable with the gear you listed. I bring a light kit with umbrellas to every wedding I shoot, but don't often use them unless the spot we've picked out for formals is really dark. Not sure I'd go out of my way to buy them, but if it makes you feel more prepared, then it's worth the cost...even if you don't end up using it.
A few things that are in my bag that I use quite a bit. A small flashlight so I can see my gear in a dark reception hall. A few shout wipes for when the bride dribbles a little cocktail sauce on her dress right before the formals, a small sewing kit, a roll of thin duct tape, and a leatherman micra (people are always looking for scissors - especially during the bridal prep).
Every litle detail is important to the bride from the napkins to the chair covers to the little box for folks to put cards in. She personally picked them out, try to photograph as many of them as you can.
Before the ceremony, coach them to linger for a second or two on the first kiss.
Check your remaining shots before the processional starts to make sure you're not changing cards while the bride is walking down the aisle.
Don't forget to get at least one shot of the GROOM alone (I sometimes forget this one).
There are a million special moments that happen at every wedding. Capture 500 of them and you will do an amazing job. So don't sweat it if you miss a tear or a meaningful look.
Good luck man!
Good luck, and I look forward to seeing some pics soon! 
