Hi countrygirl-
Yes, Darren and I have replaced our doors twice with standard doors. The first two we weren't that happy with. Mostly because we were inexperienced in installation and didn't really get them in well.
In our most recent replacements, we chose great doors, and installed them well using instructions we found on home improvement sites. It takes a bit to understand how to shim them and how to get them straight, but eventually we got it and we love our doors. Although I think the back door may need a little adjustment this year as there was a very tiny gap toward the bottom left side, we are confident enough with making those adjustments now.
I will say that our front door, on the inside, with the trim around it has NO GAP with the crown molding on the ceiling. The top door trim does meet the crown. We used a narrow ribbed door trim with corner squares (available at Lowe's and Home Depot). Much easier that way!
If you have other questions, please feel free to ask. If you want to request pix, contact us via the contact page with an email address and I'll send them along. Sooner or later I'll get around to a blog post all about doors and installation and pix will be included.