ITIL is a repository of service delivery best practice and a bit of a success story for UK government. Which, some people might think, is rather unusual (but none-the-less welcome) in the technology field.
I think that ITIL should be important for more than just IT Service Management (see, for example, here). But ITIL is changing and becoming commercialised (see my blog here) - are you aware of ITIL 2011 and the Axelos Joint Venture?
Do any of these questions affect you - or should they affect you?
I'd like to recommend an interesting survey of the last 12 years of ITIL - from ITIL v2 to ITIL 2011 and Axelos - by Brian Scott (Chairman of the BCS CMSG) on Brighttalk, which might help you decide this for yourself.