
I tend to recommend trocoxil - it's quite new, not a lot of vets have heard of it but it's flippin amazing! It's in the same family as metacam etc, but the side effects are minimal (not actually heard of a dog having any yet) and the good effects are huge.
My 9yr old Soli has been on it for about 18 months now I think, it is literally her lifeline - without it she now cannot walk due to pain, and gets so stroppy she becomes dangerous to live with for me and the other dogs.
With it... well, last time she started a course (it's licensed for 6 months on, two months off, at a once-a-month dose), she went from sofa-ridden to running and completely pain-free in 3 hours. :-o
I've also just started my 13yr old on it - she came to me nearly 3 weeks ago now with severe, advanced osteoarthritis (same as Soli), she'd been in serious pain for a long, long time (no vet treatment of any kind given :-(), and rimadyl didn't do anything for her. I decided to skip the others and go straight for the trocoxil - took about 24 hours to fully kick in but she's lost years of her age since, it really is fantastic - 90% pain free, charging around and harassing everyone just like she used to lol!
I've just learned that my 6yr old lab has horrendous arthritis in her knee (the vet's word, horrendous) and she'll be starting on cartrophen today - heard great things about that too but I've not tried it yet. She'll be getting NSAIDs too, not trocoxil as yet but in all likelihood I'll put her on it too - I've just seen it work too well not to consider it, and I've heard the same from many other owners and from a vet who specialises in hip dysplasia and arthritis diagnosis and treatment.