I read about making a gmail compose bookmarklet here but I guess this method works a little differently now that Gmail version 2 is out. The url I got as a bookmark from following the steps in this article looked like this:
This version of the bookmarklet takes forever to load for me and sometimes doesn’t load at all. I took off the #cmid%3D1 and the loading time got a little faster and the page no longer froze while loading.
I continued removing stuff and changed from ui=2 to ui=1 and eventually got a significantly faster loading compose window with something that ended up looking like this:
https://mail.google.com/mail/?ui=1&view=cm&fs=1&tf=1
This is the fastest version of the bookmarklet I could make that retained the auto-complete javacript for recipient fields. For a super fast version, you could switch to HTML version of gmail and bookmark the compose page, but I really like having the autocomplete for addresses.
To add my version of the bookmarklet, drag this link into your Bookmarks Toolbar:
I also made a javascript version of the bookmarklet that opens a new, small window, kind of like the capital-C shortcut works in Gmail.
Here is the javascript, open in new window, version:
<a href="javascript:var%20w=window,u='https://mail.google.com/mail/?ui=1&view=cm&fs=1&tf=1',l=document.location;try {%20throw(0);%20}%20catch(z)%20{a%20="function(){if(!w.open(u,'t','toolbar=0,resizable=0,status=1,width=600,height=500'))l.href=u;};if(/Firefox/.test(navigator.userAgent))setTimeout(a,0);else%20a();}void(0)"">G:</a>
This javascript bookmarklet is the one I have ended up using. Enjoy.
UPDATE
This appears to be faster now:
https://mail.google.com/mail/?ui=2&view=cm&fs=1&tf=1
<a href="javascript:var%20w=window,u='https://mail.google.com/mail/?ui=2&view=cm&fs=1&tf=1',l=document.location;try {%20throw(0);%20}%20catch(z)%20{a%20="function(){if(!w.open(u,'t','toolbar=0,resizable=0,status=1,width=600,height=500'))l.href=u;};if(/Firefox/.test(navigator.userAgent))setTimeout(a,0);else%20a();}void(0)"">G:</a>