OP here. I see a lot of folks with various suggestions, all of which are greatly appreciated.
My thoughts are this: 17-40; 35/1.4; 50/1.8 are the lenses I currently own AND would not consider selling. I need the 17-40 for wide angle, and frankly it never gets used past about 24mm. The 35L for low-light and street photos; same with 50/1.8.
I would replace my 28-135 w/ 24-105 because: 1) They are very cheap used now that it's been the kit lens for all (3) three 5d camera bodies. Many, many of those in the used/new market. 2) I may get another body, either a 40D or 5dClassic in the future.
Lastly, it's not so much overlap as it is different needs. The 24-105 and 70-200 are BOTH very versatile FLs....paired to either FF or cropped bodies. I need IS because I have unsteady hands and don't use my tripod very much--only on landscape shots. I want to start doing modeling work, and hopefully that will come in time. I don't see how the 24-105 & 70-200 would be bad choices for that type of work either. The 100 macro NEVER gets touched any more. Haven't shot a single picture with it in nearly two years.
the 24-105 is great for studio work the reasons are as follows
1) its a sharp lens even wide open at f4 its good however
2) shooting studio you are typically shooting f8 - f16 sooo f4 is fine
3) IS is really handy on this lens (just remember to switch it off on a tripod
4) the zoom range 24-105 is great for a studio no lens changes at all and you can shoot everything
5) its not too massive, its a good size not too heavy and easily maneuvored 70-200 can be quite unwieldy at times the f4 less so than the 2.8 though
overall i think you plan to use the 24-105 for your general purpose lens is a good one
i had another thought though and i think someone else mentioned it too since the 24-105 give you pretty decent general coverage i suspect the 70-200 will spend most of its time at 200 if you are using it you will be chassing the reach
consider the 200 f2.8L II primehttp://www.ebay.com.au/itm/A0475-Canon-EF-200mm-f-2-8-L-II-USM-Lens-F2-8L-Gt-5Wt-/390340094258?pt=AU_Lenses&hash=item5ae2152932
since budget is a consideration save some coin its a bit more low key 1 stop faster (no IS though) and stellar IQ
of course you can save even more and get one second hand