Word tracker is great tool, but on it's own it has limitations and I haven't used on it's own for a long time.
I tend to use the results of Wordtracker using KWE as it interfaces with WT.
KWE also parses the results from Keyword discovery which I also use.
I also use Keyword country which gives different results but they have a huge database and there is a lot lower level niches that seem to be missed by both KWD and WT.
Lately have been using Themezoom but this is a very expensive monthly membership based tool but the results are great. Most if not all the other members are using the tool to research their niches and build their sites around the siloed keyword theme structure that the TZ builds up.
I on the other hand do the same, but I also use it to find domains for parking.
This tool has shown me that even multi hypenated keyword domains receive a lot of type in traffic. The only disadvantage of this is that the niches at the lowest level tend to have few or low paying ads, but then again every penny counts and I try to milk each drop that the advertisers pay for.
Of course the 5 day tasting period at Dynadot helps too as not every domain registered is a guaranteed cash cow.