I use 7' straps on the tips, and 6' ones on the side (two each, attached to D rings). I tried longer ones for flip lines as Josh mentions, but had them spin around my oar and I did not like that.
I also have a chicken line going between the 4 d rings on the side.
For a flip line, I have two things. One is the madcatr bungee system. It is awesome once you are standing up with full tension on it. It can make getting into position more difficult when you are getting tossed around on nasty runs. I partly blamed that for the length of time it took me to self rescue on the Wind River, but once I got up I had my reflip - BAM! It's hard to imagine, that little bungee throwing your balance off, but it really does. I've also got tag lines on the inside of my frame, in case I really need something solid. However I find it hard to grip the tag line without wrapping it around my wrist, which I don't really like.