What I look for is a challenge. My last employer, though the people were warm and friendly and the environment was OK, was in the managed services business - providing outsourced IT support to multiple customers. Consequently I was encouraged (as the DBA) to be reactive to issues, rather than proactive. Any attempt at proactive measures (implementing source control, standards, even performance alerting) was robustly denied on commercial grounds. 'Is the customer paying for this? No? Then it's a no. Cheers anyway.' After 8 months I had had enough and moved onto a more challenging role.

I think things like the flagpole / fishtank (not sure of the significance of this?), decent coffee, good environment etc. are important but nowhere near as important as the core of the work. I've worked on trains and buses, in a crowded study, on hotdesks, in cafes and pubs (bars for you merkins) and I find I can normally be productive anywhere. When I worked for one large company (rearrange the letters BMI) I didn't even have a permanent office - I was free to roam the country, working where I wanted to (home, office, cafe) providing I turned in the work.

Now I work for a small dev shop. It's an OK environment - good coffee, open-plan, small staff turnover - but it's the opportunities I have to develop and implement best practices and develop my skills in areas in which I'm weak that mean I'll stay here for as long as they want me.