Post here awesome quotes from the series that you recall. I've been recently listening to Ptolemy's Gate in my car (found the audiobook for $1 at a thrift store) so I'll say

Jane: Can you feel that too?
John: Yes, but don't ruin the moment.
Jane: It was our sensor webs that went off you fool!

I'm pretty sure we've had this topic before, but here I go:

You need a proper pattern here," I said. "Wallpaper to suit your age. What about a car motif, or steam train?-Bartimaeus

Hey, we've all got problems, chum. I'm overly talkative. You look like a field of buttercups in a suit.- Bartimaeus

From the Ring of Solomon:

Bartimaeus: It was creeping after me along the gorge. Just now! Only when you turned up, it scampered.
Faquarl: Really? This is bad.
Bartimaeus: Tell me about it.
Faquarl: Yes, it means technically I may have saved you from a nasty fate.