Northern California - Mountain Bike Trail Suggestions

I'm looking to buy my first hardtail and I'm looking for suggestions on some beginner mountain bike trails that are in or relatively near San Francisco. Also, how are Cannondale mountain bikes? I'm thinking of a Trail 5. :)

MTBR has a trail review section. Click here to view. (http://trails.mtbr.com/cat/united-states-trails/california-trails/california-bayarea/PLS_4519crx.aspx)

BART to Pittsburg/Gun Point, trail to Black Diamond Preserve, up the valley from Fredrickson gate; the first mile will test you, then easy spin up the valley.

From there, challenges beckon...

http://www.ebparks.org/files/Black_Diamond_map_3-17-11.pdf

By the time you get back to BART, you will be ready for a break!

Take a look at the Lake Chabot maps and guides - rideable from the Castro Valley BART station though it requires navigating a number of busy streets and some distance to ride up to one of the park entrances, or you can drive up the main Marina entrance, park outside to save the fee. You can make it as difficult as you wish, around the lake is paved for a while, and then you hit dirt and start climbing. Honker Bay and Live Oak are difficult climbs, those you'lll want to avoid for now - go clockwise around the lake to ease into it in case you wish to bail. I was back in there a few weeks ago and my caution is the trails deep in the park have suffered because of the rains, some of the downhills are currently feel a little technical with all the ruts and wash. But, you can pick your poison. It's mostly fire road type trails, maybe the best beginner MTB park in the Bay Area. There are also regular organized rides on weeknights by a bunch of LBSs and clubs, search Google.

http://www.ebparks.org/parks/lake_chabot#trailmap