Stars $25NL Call or raise with boat on the river?

[Gavagai]

PokerStars No-Limit Hold'em, $0.25 BB (9 handed) converter

BB ($27.05)
UTG ($25)
UTG+1 ($32.15)
MP1 ($23.20)
Hero ($40.60)
MP3 ($5.85)
CO ($24.55)
Button ($1.40)
SB ($38.95)

Preflop: Hero is MP2 with 6[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">3 folds</font>, Hero calls $0.25, <font color="#666666">2 folds</font>, <font color="#CC3333">Button raises to $0.5</font>, <font color="#666666">1 fold</font>, BB calls $0.25, Hero calls $0.25.

Flop: ($1.60) 6[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
BB checks, Hero checks, Button checks.

Turn: ($1.60) 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">BB bets $0.5</font>, <font color="#CC3333">Hero raises to $2</font>, Button folds, BB calls $1.50.

River: ($5.60) T[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $2.5</font>, <font color="#CC3333">BB raises to $10</font>, Hero ?

My thought is that the possibility that villian has a flush, a straight, trips or a lower full house makes this a raise...