AVR-Chat

Okay, after getting my code to work (or at least compile, I haven't 
flashed it yet) and reading all the responses I have a new but 
related question:

I'm used to working on computers with large amounts of memory and 
processor speed, so I natually used my standared for loop 
declaration: 
for(type var = constant; condition; var++){}

is this going to cause me problems on the memory limited AVR?  Should 
I get in the habit of delairing my variable before hand (I was always 
taught this was a bad thing on higher languages which have built in 
memory management) when I program for the AVRs?

BTW: I am using the gcc compiler.

Thanks,
Daniel