Go for the 67 degree or higher apparent field eyepieces. The Naglers, Meads, Teleview and Panoptic's are the most popular. Also for small focal length the Teleview Radians (60 degree) are great. They have a long 20MM eyerelief, you don't need to put your eyeball on the eyepiece to see. With the long focal length of the 12" LX200 you won't need a barlow. I never use it. If you want to, get one anyway, but you'll see. My 8MM Radian gives me 381x and only focuses on the clearest of nights. I use it for the Moon, planets when the air is still, small Planetary nebulas and lots of double stars. Don't expect the 50x aperture rule to apply for max magnification. Once you get around 500x the atmosphere is just too much for any scope, except a real good APO refractor. I use the Panoptic 22MM 67 degree for about 75% of my observing. I get a real sharp 138x with the 12" LX200. I have the Meade 40MM at 76X which I used to use all the time till I got the 22MM. I still use it, but I just love the Panoptic 22MM. I also have the Meade 14MM UWA. Real nice for the planets and moon. It's good on lots of other stuff, I use it quite often on planetary nebulas witht the ultra block filter. At 218x most open clusters fill the field or are too big. They look great but I prefer less magnification for open clusters. Galaxies begin to loose some brightness and sharpness at 218x unless they are high in the sky on a clear night. That's why the 22MM gets so much use, it's like the perfect size. You only need 3 or 4 sizes to get a pretty good range. Things don't look all that different at 175x as they do at 150x so don't worry about a real wide range of eyepieces. Get a few expensive ones, you'll see a big difference. I saw the 17MM Nagler, outstanding!
That's it;
BOB SAL