Crawlies are often exacerbated by having the brightness set too high.
Use Avia or similar to set the white and black levels, and see how much difference it makes.
If you don't have a calibration disk, you can try the THX Optimode from something like a Star Wars disk or Cast Away for instance. I find the Optimode seems set-up more for the disk it's on, rather than a blanket calibration, but it might get you into the ballpark.
If you have a THX optimode disk, play a few scenes and see if you notice the crawlies. Make a note of those scenes, then calibrate the white levels (white boxes test) and black levels (THX drop shadow). Re watch the scenes and see if the crawlies have gone or are reduced. If so, you know that basic calibration is all that's needed. Then try some other DVDs that you'd already seen crawlies on and see how they compare to the results with the THX DVD.
If basic calibration is all you need, then buy Avia. If you decide to go for SMART III later, you're going to need Avia anyway.
Gary.