If there's one thing I can highly recommend when it comes to sports betting, it's not to be blindly loyal to any particular bookmaker. Leaving aside Betting Exchanges as there are obviously not as many around and Betfair dominate that marketplace, it is always worth your while to have several traditional bookies accounts open. Not only does that allow you to place your bets at the best possible odds, but you can also take advantage of the generous welcome bonuses that they offer.
Over the past couple of years I have cleared bonuses at dozens of bookmakers and casinos running into a few thousand quid, so it's not to be sniffed at and it's something that any discerning punter should be practising in. Gamblers get used to a particular bookies layout or have a good feeling about a sportsbook, a mate of mine only places his bets through William Hill and recently tried Bet365 on my advice because of the great welcome bonus that they offer, but he bust out at Bet 365 and he convinced himself that it was the sites fault and not his. He has now retreated back to the comfort blanket which is his William Hill account, where he got his £25 bonus a few years ago. If he were simply to open a new bookies account every month or every week he could be clearing an extra couple of hundred quid in his back pocket for the sake of filling in your details (which I use Google Toolbar autofill for by the way)
I've joined pretty much every bookie going in order to release free bonus cash and I'll be reviewing them over the next few months as some are obviously better than others, so hopefully I can give you some insight into which is the best order to tackle them.