I have a favorite saying about camera gear:


Bodies may come and go, but good glass is forever.





I really want to encourage you to invest in high-quality optics as much as possible. Bodies are updated every 1-2 years. Lenses can go for a decade without being redesigned. A sharp lens, cared for properly, will last you through multiple bodies. Their resale value is also higher. You can achieve more creative flexibility with the appropriate lens than you can with a different body. Canon L lenses will perform admirably on any EOS body.


Now this advice isn't meant to discourage you from purchasing the 7D. In fact, the move from an XSi to a 7D is pretty big. So I think it's a good decision. But don't cheap out on lenses, because that 7D has a very high pixel density and it will reveal any shortcomings of the lens attached to it.


That said, the 28-135 is a generally well-regarded lens, but I advise you to move toward L glass as soon as possible. In fact, if you cannot afford the initial outlay I would advise you to buy NO lens, continue using what you have, and save up until you do have the funds. The most common mistake I see when buying lenses is that in order to satisfy their Gear Acquisition Syndrome, they buy whatever mid-range lens they can afford, then end up with a collection of "decent" lenses, when they could have had one or two carefully-chosen "amazing" lenses. I freely admit that I myself have been a victim of this error. It takes a lot of discipline to wait for the right moment to buy, and you absolutely must know exactly what you need.


If your intention is to go "full frame" at some point, the best lenses for the type of photography you mentioned are the 35/1.4L, 85/1.2L II, 100/2.8 macro (both L and non-L versions), and the 135/2L. The 24-105/4L IS is a very versatile and easy lens to use, if you prefer zooms. Presently, the 70-200mm family of lenses are a bit long on the APS-C size sensor of the 7D for your purposes. And remember, try before you buy. Don't be afraid to walk into a camera store and play with some lenses, even if you plan to buy online. And ideally, try to rent when you've narrowed it down to one or two lenses. Good luck!