Docstoc--A great site for both legal and many non-legal specific forms.
OneCLE--A good site with many forms culled from SEC filings.
WhichDraft--Good forms and somewhat interactive.
Techagreements.com--Good site. All forms in Word. This can be accessed directly or through onecle.com. The greatest benefits are that the forms are very sophisticated, there's very broad coverage, and the search mechanism is strong. The drawback: Each form is $35.00 a pop.
Realdealdocs.com--Excellent forms from big firms. Like techagreements.com, the site is very sophisticated, there's very broad coverage, and the search mechanism is strong. The drawback: Requires a monthly subscription of between $37 to $67 per month, with the cost dependent on the length of time you commit to a subscription for.
Scribd--Not just a form site, but a site with a good deal of source material.