[bodie]

as wintermute said, only slow-play in O8 if you have the stone-cold nuts that can't be beaten. O8 is famous for ruining a straight with a flush, a flush with a boat, a boat with quads. So if you flop three 5's, like you did here, you want to bet/raise and try to drive out anyone who might be thinking of drawing to something better. Three 5's is *not* a strong hand in O8. Usually someone else would be making a boat with those two flopped 5's so you'd be drawing dead from the beginning anyway. Quads aren't all that common but they happen.
For instance yesterday when I was playing live, I was dealt:

As, 3s, Ad, Kh

The flop was 4s, 4x, Qx

The man sitting next to me raised when the betting came to him - I had checked and then called. Turn was:

7s

So - by this time the pot was close to one hundred dollars - I had pot odds to call with 2nd nut low possibility, nut flush possibility (though the board was already paired so I figured that was no good anyway) and the dream of an Ace coming on the river. So for $6.00 more I decided to call to see the river card.
Guess what - an Ace came on the river and I won high. Yes, lucky - but that's O8. The man next to me had flopped a full house, 4's full of Q's. Of course my low was counterfeited, but that's the way it goes!
A typical example of what can happen.