Completely agree with XXX Boy.
What you can do is:
1) 17-40mm f/4L USM - new: $1140 (from Oracle) or $900 (second hand)
2) 50mm f/1.8 II - new: $138 or $90-100 (second hand)
3) Sigma 70-300 (either the APO Macro Super II or the newer DG macro) - get this 2nd hand - it's a nice lens, can get the Super II for abt $220 if u scout around or the newer DG one for about $280 (w/ warranty).
4) If you've got some spare cash, get a set of extension tubes (either the 25mm one or the set of 3), You can use these for macro shooting.
I wouldn't recommend the 70-200 f/2.8, not at this stage. It costs >$2K. That's a lot of money to put up if you're not sure if you'll use this focal length.
Personally, I use the 24-70 range most.
I'd recommend going on outings and trying out what ppl have and how extension tubes work etc. Then you can make a more educated decision.