I would most certainly go glass then cmaera...... its hard if you have a nice FF but nothing to go with it! As for 3rd party, the tamron 24-70 is great but i would also go for something wider such as a 17-40 (Canon). The 17-40 isnt all that big of a purchase compared to the 6D or the 24-70, but it should still be done.
finally, get a longer reaching lens as well. Either sigmas or tamrons 70-200s are pretty good, so I would opt for one of those too.
Canon EOS 6D: $2099
Tamron 24-70 f/2.8 DI VC USD: $1299
Tamron 17-50 f/2.8 XR Di-II LD: $499
Sigma 70-200 f/2.8 EX DG APO OS HSM:$1250
Total price: $5147- not bad compared to if you bought all canon, which would be about $6800ish