OK here is my Muffin Top 7500 as I normally carry it. I know people say you don't have to carry all your kit but, if it all fits in one bag thats not too heavy, why not?
When you open the bag this is what you see:
On the right hand side is the AF-S 70-300mm G VR stood on it's front end with lens hood attached. In the middle is the D90 on it's MB-D80 grip with a 35mm f/1.8 attached (forgot to label that in the pictures). Notice the 35mm sitting over a flap. On the left is an AF-D 85mm f/1.8 sat (with lens hood attached) on top of a Sigma 10-20mm f/4-5.6.
If you take the AF-D 85mm f/1.8 out you can see the rear lens cap of the Sigma 10-20mm...
Finally, if you lift the camera out you can lift the flap covering the 18-105mm VR...
In my experience camera bags can be a pain. This is literally all my main kit (excluding tripod anyway). But I'm after a Sigma 150mm macro which is never going to fit in this bag (with everything else in anyway) and I'm also after a flashgun so I can start learning the art of directed lighting. That also wouldn't fit in this bag as it is at the moment.
My advice is to buy a bag that you can fit everything in and allow some extra space. When I got the 85mm f/1.8 and the Sigma 10-20mm I managed to fit them in and that saved me a lot of hassle hunting around for yet another camera bag.
The only other thing I would say is, if at all possible, try to keep the bag you buy in good condition. I've had loads of bags and I've sold every single one on eBay when I've replaced it with a new one. Crumpler bags are especially easy to sell as they're relatively expensive and very popular (read that as trendy). I actually sold a "Pretty Boy" and a "Messenger Boy" for more than I bought them for (they were bought new in a sale and I sold them for non-sale retail prices) but they were in excellent condition.