Are you referring to measurement and analysis tools or to tolls that make implementation of a marketing plan easier?
If the for former, these days I use hardly anything except Google, but that has more to do with the stuff I do and that once one is working with brand names and action keywords then there ain't much left to do.

If you want to find out what people are doing when it comes to spending money (the stuff that we are chasing) then you can do much worse than looking at Amazon or eBay and for getting a fix on what works look to the bigger article directories that have decent approvals systems to find out what successful folks with a track record of years are doing.

For implementation of marketing plans then SeNukeX backed up with Scrapebox are the two biggies.
TBS and now ArticleBuilder help feeding the the above.
These tools enable me to forgo paying other people to do work for me.
SEnuke and Scrapebox are synergised using private proxies and running from a VPS
And I buy in a ton of content on an ongoing basis to throw into the maw of the machine.
