A handy HTML 5 Cheatsheet (PDF)…
So why not add in a CSS3 Cheatsheet (PDF)?
20 Tools to Make the Life of a Web Developer Easier wow, some seriously cool stuff here!!
A few notables…
(also found this, which is interesting: http://leftlogic.com/lounge/articles/microformats_bookmarklet/
- http://riddle.pl/emcalc/ (nice, takes a little plinking, but nice!)
- http://tester.jonasjohn.de/ (sounded promising, but a little wonky, shame…)
And finally, a little jQuery magic to make all you Mac-ites feel more at home…