Definitely go with a hive tyrant, I personally like taking 2 zoanthropes to go with my tyrant, it helps if you spread them apart in your army to get some overlapping synapse.
Tyranids are tricky in the sense that you always have to be mindful of your synapse range. I know in friendly games most opponents don't think about the synapse or don't care but if you ever get into tournaments your opponent will be looking for anyway to beat you and taking out your synapse could really ruin your day lol. So more synapse the better!
Also hormagaunts and gaunts are cheap so don't be afraid to field a large number in several squads, their just there to block the bullets for your deadly CC units.
P.S. One of my fav units is a carn with 4 devourers. 8 strength 6 shots with re-rolls to hit and re-rolls to wound pretty awesome against troops and light vehicles.