Cryptologic (see
www.wagerlogic.com, their licensing arm) is a big one too. They power Intercasino.com (and their poker site), William Hill, and a few others. Cryptologic is in Toronto, like you and me.
Check out
www.pokerpulse.com, and see what vendors the biggies are using. I doubt iGlobalMedia (owners of Party Poker) license their software anymore, but doesn't hurt to check.
If your clients have major cash for gambling domains, in order to brand themselves properly, worldpoker.com, 7cardstud.com, sevencardstud.com, rounders.com, texaspoker.com, freecasino.com, freecasinos.com are some of mine.