Must See Places in Xi An

Hello,
I am planning my trip to beijing next week so thought of traveling one day to Xi An also to see the Terracotta Warriors... so is it one day enough for it ? n i am reaching there around 9.30 or 10.00 in early morning and leaving early at 7 another day... so how should i plan my trip ? beside terracotta Warrior which is the muct place i should see ?
Waiting for ur reply in detail.
Thanks.

Best Regds,
Prits.