Dont bother signing up at 5dimes. The bonus is not a cash bonus, it is a 'freeplay' bonus. This means that when you wager your 'free bet' and win, you only get the amount of the bet back, not the amount the wager+the bet like you would if you had placed a normal wager. In addition to that, thier prices are terrible, making you lay -110 or worse on everything.
Pinnacle is the best book out there hands down with -105 style pricing. However, I would not recommend that you deposit there until you can get the max bonus.
You may wish to check out
www.biggerbonus.com, they give you an extra 50$ on top of the regular bonus for many sportsbooks. I just signed up to vipsports through them, and ended up getting a free 50$ future wager, free 50$ horse bet, 100$ cash bonus from them, and 50$ cash bonus from biggerbonus off of a 500$ deposit.
Another worthwhile one i did awhile back was sportbet. If i remember correctly it was a 150$ cash bonus from a 300$ deposit. I believe it was 7x d+b, which is not bad at all for a 50% bonus.
Hope this helps, good luck.