I'm thinking about doing my first pork butt this weekend and want to get opinions on using the same rub I use for brisket and ribs..Thanks!

Add some more brown sugar and go for it.

You can mix a little more rub in when you pull or chop your pork if you need it. I usually like to add a little extra seasoning salt then too.
Peggy

Well, you can but I don't.

Comes down to taste. I don't like to use the same rub on everything because I like a variety of taste.

Unlike Beef, pork needs something to add some flavor to it. Sorry, but the other white meat taste like almost nothing if you don't add something to it.

I like Tom's approach add some sweetness.

Check out the links in Pork Butt 101 for a map and a finishing sauce. They get pretty favorable reviews here and if you're really adventursome, try the mustard sauce.

Pork Butt 101

Or search "butt rub" and get 200+ responses. Butts are popular around this forum