Depends on the budget
First rule in my house is to do whatever I want to the truck
so long as I don't make it hard on her. So...I ended up with sliders. It wasn't really a compromise, since I wanted them anyway. Metaltech is doing a pretty good sale right now—that's where I'd look (I have them, and they're superb even at full price).
Now that shipping is more reasonable I think it will pick up. Plus the group buy applies across all forums so I think there's a good chance. If anyone is active elsewhere please promote this!
forum.ih8mud.com
As far as first mods—the fo'real answer would be to do whatever makes it more capable or convenient for your particular uses. "Take off the running boards" is kind of a running joke here (though it really does look better).
My first 'mod' was to add a HAM radio to get my LX ready to run with the regular group of guys. Second was to sort out the "entertainment" system to bring it into something reasonably modern (VLine VL2 for me). I left the running boards on until a rather large rock (and some particularly uninspiring route-choosing) made the decision easier.