I also use a 10 gallon cooler.........but that doesn't mean it's right for you.
I guess the place to start is to already think of upgrades. Will you want to have the ability in the future to direct fire your mashtun for step mashes? Will you batch or fly sparge? Is there any chance you'll be wanting a brewstand?
I pieced my system together (still working on it) because I never even imagined making AG batches, let alone 10 gallon batches with step mashes and decoctions. So, even though my cooler system works fine for me, I wish I had thought it out more and bought some different equipment. It works just fine, of course- but it does limit my options.
Something that I think about that most of you guys don't is the weight of the "stuff". There is NO way I can lift 6 gallons of hot wort. No way. So, now, I'm wishing I had a ballvalve on my kettle, as well as a pump or something to raise those runnings from the ground to the burner. If I had it set up better, I would have a "tier" set up to minimize the heavy lifting. I brew mostly inside, so it means I lift from the floor to the stove top. That's one reason I batch sparge- I can lift my pot with my first runnings to the stove top and start that on to boil while I'm sparging. Then I have to collect those runnings and pour into my brewpot. It's definitely not ideal. When I brew outside, I'll sparge into the keggle already on the burner.