Having worked with a good number of Valley firms, my best experiences have been with the so-called regional firms (i.e., not "Big Four" but not little 1 or 2 person operations either).
A couple of suggestions:
Mohler, Nixon & Williams - I have worked for years with Kent Williams, who is superb in tax, very personable, and my personal CPA as well (http://www.mohlernixon.com/kent_williams.htm) - they have worked over the past couple of decades with a slew of startups, including many early-stage ones.
Burr, Pilger & Mayer - Roy Maynard (http://www.bpmllp.com/display.asp?catid=8,16&pageid=44) is a good guy to work with here - ditto for their startup experience.
Frank Rimerman & Company - they are highly experienced at working especially with VC-funded startups - my main contact there recently left the firm but I am sure many excellent CPAs would be more than eager to help you there.
Pricing is always a factor for a self-funded startup and I don't think any of the above firms are the cheapest (at least in relation to smaller shops) - I would put at least MNW and BPM in the "moderate" range given Valley standards. I have worked as well with many small CPA firms, some quite good, but these may or may not fit your needs in terms of range and depth of expertise, depending on where your company is at.
