i believe the best one,much better then pricey alternative...sorry windows only

Obviously is free , well needs a free registration key

http://www.donationcoder.com/Software/M ... index.html

PS http://www.donationcoder.com/ is also a place were you may found a lot of other free utils,suggest a new program to develop,and so on

I don't know about OSX, but you realize Windows and Linux do this already, right?

Also, I scanned this with VirusTotal. You might want to look at the results.
http://www.virustotal.com/file-scan/rep ... 1286654600

I have ksnapshot in Linux and it does a great job. Even has a pause button you can time so you can get those mouseover messages and dropdown lists working before it copies the shot.

sure they do but they do just the most basic capture that for me is often is insufficent
it is for some reasons if there are so many screnshoot sw even for linux

About the virus alert i can't say much but i suspect false positive
(my antivirus never detect anything, and i am using from years )

PS looking better the result of your link, the file was tested with almost 40 different antivirus:
about 36 found the file clean
1 detect something vaguely suspicious
2 found something but they do not concord on what is

and i believe on 40 test 2 false positive are not surprising

i use FastStone capture which you can dl free also. =)