Street food, street food, street food!  Don't pass up the awesome street food sold throughout Sierra Leone.  My personal favorite is the fried plantains, but there is so much to taste.  Don't pass anything up.  Sierra Leone has some of the best fruit in West Africa (along with Ghana).  Added bonus - it's super cheap!
For those of you worried about your stomaches, I ate anything and everything I pleased and never had a single problem.

Give several days to get to and from and bring more triple what lonely planet says in the W. Africa guide. It is time consuming to get there, the poda-podas only leave when they are full, as is the way in all of W. Africa. It took me over 2 days to get there, and it is very difficult to get back because it is a small town you are trying to leave from, arrange for transportation before hand, or make it an adventure and find your own way back. I rode a motorcycle with a 17 kilo backpack on for 2.5 hours.

Try Paul's Lobster in Lakka Beach

if you go to freetown dont forget to visit chicken champ snacks , dont change money on the street.