Hi IRT,
Robert has given you some great advice and I'm with him- go the 6" dob.
6" is considered entry level for deep sky observing. I had one and it was a great performer. Yes they are bulky, but I found it easy to carry- if you carry the tube separate to the base. I'm a featherweight and I had no problem carrying it. Dobs tend to give the best aperture for your $dollar$.