With SaaS becoming much more mainstream, Ray Wang at Forrester has put out a timely report on SaaS Licensing.
Not much I disagree with.
I would add one other consideration - plan ahead for expansion/contraction scenarios as you sign multi-year deals. Even though SaaS is supposed to be a way to make variable fixed IT costs, the SaaS spend can itself become an albatrosss over the years unless you negotiate to keep per user costs fixed as volumes increase and acquisitons happen. On the flip side, given the economy you also want the ability to reduce the licensing volume on an annual renewal basis.
