I hope you read the fbsd-stable mailing list and understand the risk of upgrading from 7.0 to 7.1.
For example
Big problems with 7.1 locking up :-( or
FreeBSD 7.1 Breaks re and rl Network Interface Drivers.
I haven't used FreeBSD ports for some time, but I know that on OpenBSD many ports require the X libs to build/compile things.
Why remove those libs?, just to save a little disk space?