I'm curious what IGPs people are running out there in dual-stack land.  What is HE using for an IGP?

The only real choices are OSPFv3 and IS-IS for a dual-stack environment, right?  

I've noticed a lot of people talking about IS-IS lately.

I played around with it a bit using GNS3 and found it pretty easy to set up once I figured out that you had to set a unique OSI NSAP on each router for it to communicate and identify itself to other routers.  Once that was set up, all I really had to do was turn on IS-IS on each interface (here's a snippet):

interface Serial0/0
 bandwidth 64
 ip address 192.168.10.1 255.255.255.252
 ip router isis
 ipv6 address 2001:DB8:10::1/127
 ipv6 router isis

router isis
 net 49.0001.0100.0100.1001.00
 metric-style wide
 log-adjacency-changes
 default-information originate
(yes I was playing with /127s for serial p-t-p interfaces)

The NSAP is the "49.0001.0100.0100.1001.00" part (google NSAP if curious).

The neat thing is that IS-IS can carry data for both IP and IPv6 in a rather transparent manner.  You just set up the router section, then tell it to route ip and ipv6 with the "ip/ipv6 router isis" statements on each interface.

Yeh I set up a OSPFv2/v3 experiment also.  Was pretty simple to set up one I figured out that you have to use "ipv6 router" statements to set it up per interface rather than a normal "router" section with network statements.  Although "default-information originate" is done in a ipv6 router section.