I use a cast-iron brick, with holes in the removable lid and I fill it with wood chips. It sits on the 'flavourizer' bars of my Weber. Ang and I broke down 10 years ago and dropped (what we thought was a lot) some serious coin on a BBQ. A Weber Silver B. Looking back, that was a very good decision. That thing has only cost me a $ 13.00 igniter. It lives outside and gets used year-round. People all around me have replaced their BBQ at least twice since then. Some have those massive all-stainless-looking monstrosities with the big fat knobs and a dozen shelves, doors, etc. The things fall apart, and replacement parts are hard to come by. When I gave it my annual cleaning this spring, the burners were still rock-solid. The grates are stainless and show no wear to speak of. Highly recommended. A couple of people I know have Napoleon and Vermont Casting BBQ's. They are also very happy. Bottom line, a good Q costs the best part of a G-note.
So much for gas. It is hard to beat a real charcoal jobbie, like a Weber round ball.
The draw-back of using the wood-chip-filled brick, is that it has to come to temperature before the 'charcoalification' process to begin, wasting fuel. But once that thing starts wafting smoke into the ol' Q, look-out! Those meats take on a flavour, all smokey, right quick. I use alder, hickory, mesquite, apple... and even tried cherry (we didn't like that so much..as we didn't like oak or particle- board..LOL)