Aaron,
I'm absolutely in love with the early Lamborghinis. A car like the Islero is waay underrated in my opinion. I just saw a picture of one JR used to work on in his shop. Nice blue color.
Very cool cars. I hear the S models are worth the jump.
I prefer the early 350GTs and 400GTs. The Miura is of course a perennial favorite. These things sound so fantastic! Have you ever heard one? If you haven't you'll be very pleasantly surprised I'd wager.
I drove JR's ex-Steve McQueen Miura close to 100 miles and took the car in excess of 220kph. The car ran incredibly well and never missed a beat. There was only one thing wrong with the car. The front right headlight was a little sluggish getting up from the lack of use (shame on you JR!). He pampers the heck out of this thing, which made it an additional privilege to take on such an extended drive. The instruments were spot on. None of the bouncing around, although I did test drive a 1976 Fiberglass 308 GTB that had that problem. The needles would sway here and there whenever I hit a bump or went onto a driveway. I don't think its typical and once sorted you shouldn't see this sort of behavior. Experts, please feel free to correct me. Given the age of the car I was astonished as to how incredibly well it ran. Even after sitting for a while. You really need to find an expert mechanic for these things though. Not too many people can make a car like the Miura run reliably, fast, and putter around in "around town" traffic without even a hint of overheating or carbs misbehaving or stalling. Just fantastic. If you're ever in the market for these cars don't believe the guy when he tells you none of them run really right because they are so old. Oh no, these things are a dream to drive, albeit a bit cramped.
280 is my personal test track when I head home to the Bay Area! Hehehe. I once got pulled over by a police officer for speeding down the 101. He politely told me. "Sir, there is a place for that kind of fast driving, and its called 280. Don't let me catch you doing those speeds in these roads again." HAHAHAHA!
Be careful with the 456s. A friend and parts supplier in Ferrari of Los Gatos went out of the way to warn me to look only at the Ms. Be very wary of the older (say, 1995) 456s. I think they had a lot of bugs in them. I do believe a lot of the fixes are in, but they still suffer from less reliability. I too thought of one when my wife asked me to get a family car. What a rocketship of a "family car"!

I'd vote stickshift too, even though salespeople have told me they are near impossible to find.
Cheers