I'd say try some general words that don't have anyone else bidding on them as a test and bid low ($0.05).
To add to this though, I would only do this if your product was a general consumer good that almost anyone would buy.
I'll spare everyone my usual speech now, though. ;)
If you do use general keywords, however, and use them as broad or "phrase" matches, I would strongly suggest using negative keywords to help improve your relevancy.
AWA
I hope it is OK for me to provide links here. If not, Mods please remove.
The FAQ revolving around 'keyword matching options' is here:
[adwords.google.com...]
And the page on which the Keyword Matching Tutorial is available is here:
[adwords.google.com...]
AWA
To make up an example, "skiing" is a pretty general term, but if you're a skiing area in region X, then advertising on "skiing" in just region X may work nicely for you.
This works if your not also advertising nationally for the same general keyword. If you are, you'll just end up driving up your national and geotarget prices in those geographic areas as your ads will compete with each other for which one gets shown.
However, my logs from that period were a great source of keywords from which to build more content!
So, I would recommend a brief period with a low budget to test ROI,CTR and also to use as a keyword mining tool.