Rod
M83 was one of my first choices as well, but I soon found out about the Dobsonian 'hole' - it's not impossible to find but the closer to straight up you go, the harder it is to move the scope exactly where you want it.
I found the sombrero an easier choice and the globular clusters are AWESOME
Other eye poppers rightnow for me are the nebulas near Scorpio (Lagoon and Triffid [I think])
These were my first 'real' nebulae (if you don't count the coal sack)
Grab a sky chart - and maybe a program like Stellarium (Free) and have a look around - a Messier catalog is also good to have (lots available on this forum)
Gee I hadn't realised I'd been typing this much. Just get out there and HAVE FUN!!!
Andrew