I don't believe you can do both - at least not very well. When you're at a client meeting and the client is speaking, do you tend to be a listener or a notetaker? For my money, in a contest over recalling and understanding the entirety of the content, and truly connecting with your client, I'll take the listeners over the notetakers any day.
Try this simple experiment: Go to a meeting with a colleague and have one of you take notes. When the notetaker debriefs the listener, you'll be surprised at how much the notetaker missed. As notetakers furiously take notes, they work so hard at capturing everything, they always miss something. They can't help but focus on what they're writing while new content is whipping right by them.
I might also add that having the client talk to the top of your head doesn't exactly facilitate eye contact or help you assess one's demeanor either. The only notes one should ever take during a meeting are deadlines and lists of deliverables. (It can be important to most clients that they see you writing down this kind of information.) You want notes? Take a few moments after the meeting to jot down the most salient points for future reference.
Next time your client leads an input session for your team, rather than bury your head in your notepad, make eye contact and listen - really listen - to everything being said and how it's being said. You'll be surprised at what you take away from it.