Also, try out the Digital Fish BLOCKFISH compressor. It's a free plugin and I use it all the time. It adds a bit more color and excitement than the RComp, which is my go-to compressor for transparency.
Like everyone said, you really have to experiment. If I were in your shoes, I'd concentrate on getting good levels out of the mic and pre. I'd use maybe just a little compression (low ratio, maybe 1.25:1 or there abouts) and a lower threshold IF the compressor adds a fuller sound. With good singing technique, you should have a pretty good take. Sweep around with parametric EQ on the track with a Q around 2 or so. Boost 6 - 9 dB and move all the way from 20 Hz to 20 kHz. Take notes as to what you hear, and what you might like to cut or boost. Do the same thing except cutting 6 - 9 dB. What helps the sound?
Search around for tips on compression; there's tons of them.
I like the Sonitus reverb a lot. It's easier to dial in a good sound than the Rverb or TrueVerb. It also doesn't kill CPU resources like the Timeworks stuff. I like the reverb to be just barely noticeable. Sometimes I'll compress it after the reverb to mesh the sound a bit; sometimes it's after the compressor. The really neat thing about Sonar is that it's flexible that way.
Play around; you should be able to get a good sound. I don't like that microphone, but if you can get a good sound out of it, imagine what you can do with a better one. I find that whenever I feel the need to upgrade, I spend some time with my mixes and tracking, and I realize that it's me who needs improvement, not my gear.