Patching and Plastering - worth repairing?// patching techniques

This is actually two questions in one:

1) I'm about to repaint a small room in which sections of the wall have cracks or sloppy plastering. While I'd prefer not to overhaul the whole room, I'm wondering if it is easier to replace the existing lathe and plaster with drywall on a couple of the walls? Are there any opinions on the pros and cons of simply repairing a bunch of uneven spots vs pulling it all down for some smooth drywall?

2) Whether I repair the walls or put up drywall, I'll still have to get a smooth finish -- the other times i've worked with any kind of skim coating, i've never been successfull getting a totally smooth finish. Any advice for how to get a nice smooth finish on the walls? Is there a particular product which goes on smoother than others -- especially when covering broad areas which are pock-marked with small indentations.

Thanks for the help.

http://www.doityourself.com/patch/index.htm

Any time you mess with old plaster, you are asking for trouble (At least in my experience)! Removing one small section leads to another section and so on. Salvaging it is the best way to go, unless you want to gut the whole room. I have a friend that used a product similar to wall paper. It went on like wallpaper, but covered all the defects in the old plaster. It's made specifically for this purpose. He then painted it, and it looks great.

http://forum.doityourself.com/showthread.php?threadid=88109

I have worked my way through three rooms of our 200+ yr old house full of cracks. A contractor friend recommended chipping along the crack down to the lathe perhaps 1/4 in width. once free of loose material. i then covered crack with fiber tape and applied joint compound as if it were drywall - three or four layers. so far, i have yet to see a crack reappear in the 16months since I started.