New Kettle question

Hiya folks,
I am a relative newb brewer, been doing it for about a year mostly partial mash, and I am ready to step up to all grain. I have just acquired an Igloo 10 gal beverage cooler, a stainless valve and bazooka tube.
My question is, what pot (size etc.) should I get to go with it? I guess the parameters are, not so small that I can't make full use of the cooler, and not so big that the cooler isn't big enough (and I don't go broke buying the kettle). More info: I have a couple of primary fermenters, one that can handle a max of about 5.5 gal and the other probably 6 or 6.5 gal. I would like to be able to make a 6 gallon batch of barleywine, or maybe use both fermenters to make 10-12 gal of something less big.
I have tools and am pretty good at tinkering, so whatever pot I get I can handle installation of valves & such, but don't currently own a cutting torch.
Any advice is appreciated.

*edit: ok, from reading other posts, and looking at the available profiles in BeerSmith it is looking like 15 gal may be the correct size. Let me know if I am wrong, and any info on good deals going on right now would be helpful.

My best advice is buy the biggest pot you can comfortably afford and be able to get to a boil. (Within reason of course....no 15,000 gallon bohemoth!). You won't regret it.

+1 on Hammy. I started AG brewing with a 40qt (10gal) pot that I picked up for about $70 at a restaurant supple place. It's great for 6gal batches. I'm beginning to build a 3 keggle brew stand, and you could make a keggle quite easily. If you look/ call around, you can find an old 15.5 gal keg for about $30. Then just cut the top off (you can use an angle grinder) and pop a valve in there and you're set for 10 gal batches, assuming your mash tun is big enough. Look up videos on keggle conversions.

I've always used a 15 gallon kettle for 5 and 10 gallon batches. You just have to be carful with the latter.
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