Head hunted?

I got an email out of the blue last week regarding a job offer. It's from a recruitment agency, so who knows what's actually going on, but I have said that I am interested in hearing the girl out. I'm not actively looking for a new job - I kinda like where I am at the moment, but things have been happening in work that lead me to believe that at least keeping my options open is a good thing. My boss, who is a friend of mine, has had a rough time of it since the New Year, so I am a bit apprehensive about putting him under more stress. He wouldn't begrudge me going for a new job though and I'd at least have the decency to let him know what the score was. There is also an outside chance that, if I were to be offered a better salary/package elsewhere, that the company might go some distance to better my current package or match it, so I could get all the benefits with few of the disadvantages.

That's all speculation as I've yet to get back to the girl about talking to her. I've not even updated my C.V. as yet. I don't see the point unless the offer is worthwhile.