Airport Express as base station - Time Capsule as extension?

[patashnik]

This might be a really simple question, but here goes:
I have ordered a Time Capsule and an Airport Express. I would prefer to use the Airport Express as the base station connected directly to my cable modem, and put the Time Capsule in a different room to handle the backups. Other than losing the 2.4 and 5 GHz dual capability, are there negative side effects to this that I don't see?

The reason is limited space available where my cable modem is located.

 

[Matthew Yohe]

I'm not sure how you'd "lose" the dual compatibility, since you can host a WDS system on the express, and have the Time Capsule connect to it, and thus extend the network further. Is there something I'm missing?