Listening to Perfect Strangers album at the moment and when I first listened to it, I wasn't sure. But I started to get into it, it's kind of fresh, and shows Deep Purple on Top Form, iwht a more modern sound but one distinct difference is, although ian Gillan has an amazing voice, it is clear that since he left in 1973, his upper register has changed completely, but still has a good range. But as a Whitesnake fan, Burn is again, an amazing record. Also, In Rock is a strong and really cool record. The obvious choices would be In Rock, Machine Head, and even burn. I might put forward that The Battle Rage On is a pretty decent record.