Will it adversely effect my SE rankings if I switched domain names? I would like to switch my lingerie store to www.LaLaLingerie.com (I'm sick of people thinking I'm running a porn site because of the Hustler name...). If I make the switch, will I lose the rankings I've busted my a$$ to achieve?
I believe you would, you would also need to get links to you changed. Why not just setup a second site and build it up for a few months whilst leaving the hustler one running ? you can drive traffic, link from it, add coop (if you havent) to it. etc etc If it earns more than the cost of the domain and hosting (without any work) then just leave it. Aged domains seem to be getting more and more valuable anyway.
Switching domain names will blow your rankings out of the water. Better, as already suggested, to build a new site from scratch with the new domain name and let it build alongside your existing domain.
A 301 would fix that... I've just done this for a client.... Basically, you should see the results drop off for a little while, but so long as you use 301's from all the old pages of your site and point them the the relevant new pages, those rankings should start to climb again pretty quickly... The use of 301's is incredibly important in terms of getting those rankings back on the new domain... Are you going to do a complete redesign too?