Two Part Poll (Poll + Hand Post)
 

First round at the table, no reads.

Party Poker 5/10 Hold'em (6 max, 5 handed) pokerhand.org hand converter

Preflop: Hero is MP with J[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, Button calls, SB calls, <font color="#666666">1 fold</font>.

Flop: (7 SB) T[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, Button calls, SB calls.

Turn: (5 BB) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, Button calls, SB calls.

River: (8 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks,

River
 

I decided to check with the button still behind me.

River: (8 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, <font color="#CC3333">Button bets</font>, SB calls, Hero?

Is overcalling good or bad here?

Re: River
 

[ QUOTE ]
I decided to check with the button still behind me.

River: (8 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, <font color="#CC3333">Button bets</font>, SB calls, Hero?

Is overcalling good or bad here?

[/ QUOTE ]
You're winning way more than 1 in 10 times. Most general 5/10 monkeys would pop the turn with a T and we're definitely good barring running clubs or a K.

Re: River
 

[ QUOTE ]
I decided to check with the button still behind me.

River: (8 BB) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, <font color="#CC3333">Button bets</font>, SB calls, Hero?

Is overcalling good or bad here?

[/ QUOTE ]

good. The overcall doesn't mean that much here since you are very likely to have him beat. I think you should have just bet it to begin with.