Yep - that 25-50 GB limit you've heard about isn't a hard limit.

I was going to post on this very subject in my "Understanding SharePoint..." series, but luckily for me :) JoelO beat me to the punch on this subject :). I have seen this statement being made incorrectly NUMEROUS times.  

See his post: How large for a single SharePoint content database?. 

My team and I as well have had to "correct" some misleading statements about database limits. The bottom line, as JoelO eloquently puts, is there is NO product group nor physical Hard Limit other than what your SQL infrastructure will allow, and we support very large databases.

It really boils down to what your Service Level Agreement (SLA) is with your end users, or IT team is when it comes to the "Best" recommendation for content database size in YOUR environment.

Bottom line? How quickly do you need to recover in case of a catastrophic failure.

Also see the official product group stance (Posted by Joel of course) on the Product Group site:

 - Keith