Are you guys using flat or riser bars with your frames? I've currently got some narrowish flats with bar ends but I'm thinking about trying some Easton low rise I've got lying around (without bar ends obviously! :-))

Whatever puts your hands in the right place! It'll just depend on your frame/fork/stem combination though obviously the typically higher front end means that for some, any type of rise on the bar is too high.

It's a 29er scandal, 100mm rebas and 100mm stem?

Go W-I-D-E with short stem

Riser or flat with sweep

And depends on your preferences and size.
I use flat bars and a 90mm stem.

Wide low risers and a short stem for me.

As others have already said, it depends on what you ride and how, and what sort of shape you and the bike are. But you knew that already didn't you, so for reference…

I'm 6'3", have a 19.5 Scandal, 120mm Rebas, run a 70mm stem and Truvative flat bars of about 700mm width, with a 10mm spacer. That puts the bars about 50mm beneath saddle height, which is 32" from BB.

I used uncut Fleegles last winter – really liked how they felt.

I've discovered Midges drop bars. Brilliant.

Large rigid Singluar, 120mm stem H-bars
Large Niner AIR, reba 100mm, 100mm stem, wide niner bars

Bars are personal things.
120mm stem and flat bars currently.
Jones bars and 130mm tems in the past.
J.