I debated the same thing as you going up from DC.
Honestly that trip up is no fun. On the train you can relax and sleep. You dont have to worry about driving, traffic, tolls, DRIVING IN THE CITY, etc. The train takes about 2.5 hours or so from bmore. Driving will take you 3-5 or more depending on traffic. The train dumps you right in the middle of manhattan. Personally i think its worth it for the train. It should be around 130-160 r/t
If you throw in gas, tolls, parking, that probably adds up to a good 70-80 bucks? I guess the question really is how much is time and comfort worth to you?