As an alternative to Scott's suggestion (upgrading to the newest 7.4), you could update your postgresql installation to 8.2, or if you can wait a few months, 8.3. There are *huge* performance gains (I recently made a similar switch and everything is blazing fast). Please note that this will require a dump/restore of the data and more involved testing, so only do it if you can devote the time, money, and energy.
As far as analyze goes, you should be running ANALYZE VERBOSE, or better yet, VACUUM ANALYZE VERBOSE (see
http://www.postgresql.org/docs/7.4/interactive/sql-vacuum.html ) so you can interpret the output. The vacuum also helps manage disk space, and this isn't a big performance hit because it doesn't require exclusive locks (though a VACUUM FULL would, again, read the docs). In fact, you should be doing this regularly, daily if possible.
For me, I have a 30 GB database cluster, and vacuum/analyze takes about 3 minutes, though YMMV. You want to look for output regarding FSM pages and relations and adjust as necessary (otherwise you're running into index bloat).
I think Scott covered all of this. Alternatively, you could look to upgrading your hardware (multi-core x86 hardware is very nice), but without knowing your needs, usage, or budget, I can't make that determination.
Hope this helps.
Peter
