I am a big fan of Google Webmaster Tools as it is the only tools available that shows you the big picture. It removes the risk of personalisation and different data centres that can swap the results of other tools.

If you have to pay you may as well just get Market Samurai as it is more useful than just a ranking tool.

I uses Rank Checker for most of the time. But do note that all rank checking tools are not 100% accurate.

Why look for the others when free Google Webmaster tool is available,I think its results are most accurate.

I also use rank checker to find out the rankings. alexa is also an effective tool

Googles WT and Google Analytics can tell you whatever you need to know. Especially handy for e-commerce.

you can use the tool webceo as well.

i just use Firefox ad-don for PageRank, Alexa Rank, Compete Rank, mozRank its simple and reliable.

Another Rank Checker user here. Yes, it is not 100% accurate but well i do not think there is a tool that is.. :-)