My rule of thumb is if you've gone to all the trouble of getting a database connection (often the most expensive operation) you might as well use it. Let the db do all the heavy lifting, it doesn't mind.

I often find that for reptitive data a long thin table wins over a short fat one. Everything gets easier. For what its worth my money would be on klassa's multi-row version

Rather than update the data you could simply add a new "set" with a unique key, which, in another table could be related to, say, a user and a date. A retentive web admin would then have lots of historical data with which to bore the pants off everyone. (charts, graphs, top 10s, oooo!) :-)

And if, say, you're using something like an HTML::Template loop to display your data you'll be looking for an array of hashes which the mighty DBI is happy to provide.