Let’s cut to the chase.  The 2.1 firmware is out and now available for download on the iTunes store.   Unlike the previous upgrade, which provided such descriptive info as “bug fixes”, the release notes provide a lot more info:

iPhone 2.1 Software Update

iPhone version 2.1 contains many bug fixes and improvements, including the following:
•  decrease in call set-up failures and call drops
•  significantly improved battery life for most users
•  dramatically reduced time to backup to iTunes
•  improved email reliability, notably fetching email from POP and Exchange accounts
•  faster installation of 3rd party applications
•  fixed bugs causing hangs and crashes if you have lots of 3rd party applications
•  improved performance in text messaging
•  faster loading and searching of contacts
•  improved accuracy of the 3G signal strength display
•  repeat alert up to two additional times for incoming text messages
•  option to wipe data after ten failed passcode attempts
•  Genius playlist creation

I’m installing it right now and see how it goes!