What brand of dictionary do you use? Book, or online?
I've been using Chambers for the last 20 years or so because it has a lot of archaic, obsolete, Shakespearean and dialect words, plus good etymologies. I've had the same one for so long now that I find I can open it and be within a few pages of the word I'm looking for (without a thumb index).
It's often faster to look for a word online, especially if I'm writing anyway, but there's a ritual to the book that I like, even if it does weigh about two kilos. If I really want to get into the etymology (handy when writing historical fiction) I'll use the OED online.
I've never been tempted to buy a new dictionary because most of the "new words" they add ("bromance", etc) are prevalent in the culture anyway and will probably go out of circulation or become cliches quite quickly. They're basically just memes. Urbandictionay.com can answer any truly arcane ephemera. I'd rather use a word that was coined 200 years ago and which hasn't been seen since Dickens. Much more fun.