Yes,I was trying to answer you.I have not even seen desire hd,but used both wave 2 ,desire and hd2.Last year I was looking for a phone with a big screen for watching movies and hd2 was the biggest one available at that time.Bought it without thinking about battery and started regretting just after 6 months.Now it runs froyo seamlessly,but the battery has gone worse,bought desire(as it was available locally for 23.5k)sold it in 2 weeks(barely lasted a 2hr movie with rockplayer).
Now a friend of mine with similar requirement bought a wave2 and it plays all formats out of the box smoothly and it easily lasts a 2hr movie with >50%battery remaining.
I have no idea about defy,but it`s audio quality will be better than HTC.All htc phone I have seen or used(hero,N1,HD2,desire)have pathetic audio quality.Even my el cheapo E5 sounds better than HD2.
Apologies,if my previous post confused you.