The Markthalle is a bit of a Hamburg metal mecca. If a metal band has been to Hamburg, they've…read morealmost certainly played the Markthalle. It's a mid-sized venue, which (I assume) holds a few thousand people.
There's no seating, thankfully, but around the stage the standing area is tiered by quite high steps, meaning that even the smallest person will have a good chance of beign able to see the stage.
Tip: The beer is reasonably priced (for a concert venue) at EUR3, but you can easily bring that price down by picking up a few cups which all have a EUR1 deposit, which metallers don't seem to care about so much. Without trying to find any cups, or even moving from my spot, I brought the beer price down to EUR2 per beer :)