Mobile Optimized Sites

I did a poll a while ago addressing the question of what devices people used during a typical day to do their e-mail.  The results were reported here and showed that 38.2 percent used their SmartPhones.  Given the dramatic increase in the use of SmartPhones, it becomes important to address the issue of website design.  Websites are normally designed to be accessed with a computer, a notebook, netbook, or desktop computer.  However, SmartPhones now have browsers that are capable of rendering full websites albeit in a rather reduced space.  It is pretty easy using touch gestures to increase the size of a part of the site that you're interested in and, in fact, you can also use a double-tap on the screen to resize a particular column for better viewing.  I normally do the latter on multi-column sites so that I can read the substantive column.

The issue arises then of whether developers of websites should provide mobile optimized versions of their sites and, if so, should the mobile version come up automatically when the site is accessed by a mobile device or should the user be given a choice by bringing up the normal site and including a button for accessing the mobile version?  I've changed my mind several times myself as to which of these I prefer.  If you're accessing this site with a mobile device, you'll know that I've already implemented the automatic launching of a mobile optimized version of the site.  

Please let me know whether you prefer sites to automatically launch a mobile version of the site, whether they should launch the normal site and give the user the option via a button of launching the mobile optimized version, or do you think sites are fine as they are and don't need mobile optimized versions?  I'd greatly appreciate it if you would leave a comment describing your preferences.