Lots of valid points brought up above (by merlyn et al), I'll just add my two cents of information that no-one has touched on yet.

When creating an ext3 filesystem, mkfs.ext3 reserves a fixed number of inodes (calculated using of the filesystem and block size). That is the limit of number of files you can have on this file-system. If the partition you are on is very large this won't be an issue for you, but you should probably check whether you're in danger of reaching that limit, execute "df -i" for that. The only way to increase the number of available inodes is to recreate the filesystem (with mks.ext3 --number-of-inodes $n), you can't change it on an existing filesystem.

ReiserFS (v3) is a lot better than ext3 at handling small files (wastes less space and is a lot faster), and it also does not have the inode limit problem, so you might want to try using a Reiser partition if you want to go on with the system as it is.