hitrek,
The base camp trek is amazing! Everyone should do it. And, it doesn't cost that much considering what you get.
We had 5 trekkers who went with us to Everest base camp. They got to stay at base camp for 3 days and experience what it's like to be among all the climbers and Sherpas and watch the Puja ceremony.
If you can time it, I would suggest you go with as part of a climbing group. We all met in Kathmandu on April 4th and arrived at base camp on April 18th. The trekking package was 3 weeks and included everything expect some meals in Kathmandu and extras like soda and alcohol etc... They did have to pay for the airfare to get to and from Kathmandu.
Check out Mountain Trip's website. They are a great company and have one of the best cooks on the mountain.
They don't have trekking info listed but you can contact them and they can send info
http://mountaintrip.com/ Cindy