I used to work at Gunderson, so I can give you the perspective of a Valley law firm. Here are the things they don't want you to know:
-It's a forms-driven practice. Most of what they do is change the names on pre-existing docs.
-They are all (Gunderson, Wilson Sonsini, Fenwick, Cooley, etc) willing to defer fees, usually up to $15k. This doesn't mean you don't have to pay, it just means you don't have to pay until you get funded.
-They'll all offer 10-20% discounts on fees for the first year
-Equity for legal work is definitely unnecessary. If a firm wants to invest, they'll ask for warrants. Up to you to give them.
That all being said, when you go out for fundraising, it really helps to have a well-known firm as your counsel. The docs you use, and your corporate book, will all look familiar to the VCs during diligence. Having a no-name small firm is likely to run up the legal bills on your financing and can sometimes kill the deal if your firm didn't know what they were doing. Or they can over-lawyer the financing docs because they don't understand industry standards. Basically, you want no surprises, so go with a firm everyone has heard of.
If you need legal advice because it's part of your business model, your best bet is to become an expert yourself. Second best bet is to get an attorney as a co-founder. You don't want to pay as you go for something that's essential to your business model.
Last comment: don't ask lawyers for business advice. They're terrible at it, because they're trained to be risk adverse. A lawyer understands rules and risks, not strategy and profit. No matter how much a lawyer says he can offer business advice, never pay for it; his hourly rate is only worth his perspective on things he's trained to understand.