Interesting responses - we specialize in title tags and descriptions. There is no uniform practice as such. I disagree more with Tom on the above, but he is also right! The suggested method by Alick is I believe still generally the best way forward.
That said as Tom pointed out clickability should also be an integral feature in how you form the Title tag and description. So there is a trade off - and difficult often to find the balance SEO -v- Clickability. High traffic pages should have alot of thought and consideration - impacts can be massive.
The positive is with the new search traffic data available in WMT's you can try a few options over several weeks. In the new WMT's you can monitor each page more accurately and the effect of Position, Impressions, Clicks and CTR changes. Our experience is that with changes to the Title & Description & the subsequent Clicks on page google re-evaluates "the page relevance to the query" to answer a "searchers query". Google re-sets or re-tests you. Google either then "publishes the page on more or less searches" and google monitors searchers behavior on the page when people click through, for stickiness.
A good Title tag will have strong keyword elements and this can be be measured in WMT's as Google places the Result on more "searched pages". Immediately after indexing the page position may drop and likewise CTR. However the clicks go up. Why does this happen? It is because google believes the new result answers more searchers queries. Then the google tests how people respond to the page when they click through - if positive the page position climbs on the new pages - if there is no stickiness (ie they pogostick) it declines.
If google believes the new page is answering a "searchers query" then the page ranking generally will slowly increase, and likewise CTR.
Anyway maybe got a bit off track. But feel free to ask any questions. ps Yes I know google state CTR is not a ranking factor however they do take stock of what customers do on a page.