I'll take a contrarian view here.
There is nearly no value in going from cat5e to cat6a in almost all office environments.
10gb copper is nasty, expensive, and flakey. It uses far more space than 5e, is heavier, and is harder to install. You have to fully test the entire cable plant including your patch cables if you want it to work. And by test I mean "use a cable tester" not "plug a computer in and watch a link light come up". And it gets you nothing unless you're going to actually run it at 10gb -- because 1gb works just fine on the cheaper stuff and doesn't work better on the expensive stuff.
If you're going to be going 10gb/sec because you have legit reasons (you do geology / video / VM image work / etc) -- skip the copper. Go straight to fiber. But even that only gets you 10gb because the 40gb standard requires 4 pairs per link.
Another option is to only wire up those specific ports that actually need the 10gb over copper and just use 5e for everything else. Otherwise you'll be spending 10x as much money as you need to for those VOIP phone ports.
If this is a greenfield deployment just have them run conduits and leave cable pulls in place -- that way you can pull what you need right now and replace it with what you need later, rather than spending a huge amount of money installing FDDI and ATM everywhere.
No great choices...