In terms of actual colour grading programs, there is a Lite version of DaVinci Resolve which is very good (and perfectly adequate for anyone who is not making something in 4K or Stereo 3D). Also, if you want to pay for something (though I actually prefer Resolve) then I would recommend either SpeedGrade or Apple Colour. My personal favourite out of these two options is SpeedGrade, but that is partially because I edit in Adobe Premiere primarily and the Adobe products allow for very smooth workflow between them. My personal preference out of the three would still be Resolve, and there seems to be a fairly large proportion of the professional film industry that agrees!
What tools are you using in Final Cut? When you grade in a specific grading program, you get given offset, gamma and gain wheels for each of the highlights, midtones and shadows - as well as overall controls too. You use these to pull the luminance band towards a specific colour or adjust the "brightness" of each band. For grading within an NLE, you have done a good job, as the vast majority of professional film-makers use a dedicated grading application.
In terms of matching shots, I usually go through all of my shots correcting them so that they all match. Then I go and apply a stylised look/grade on top of that, which helps to give it the filmic look yet match all the shots at the same time. It is a lot harder to match shots when you have already graded them, since you are both working with less colour data and also you will be distorting what colour you have left far more. This can lead to artifacting and it makes compression problems and noise in the original footage far more obvious.
If you are shooting in a dark environment, there is a plug-in called Neat Video (I don't know if it is available for Final Cut though) which is very good and I highly recommend it. If you don't want to grade fully manually, and would rather grade within your editor, then I would recommend the Magic Bullet Suite by Red Giant. They are very powerful plugins, and though they don't usually allow you to push your footage as much as a dedicated application would, they are still very useful if you are looking to roll a project out quickly and don't want to double your editing time.
Apologies for the long post, and I hope this helps!