^^ Not really, but there are some noticeable difference in IQ at same focal lengths too. Appo has a huge collection of MF lenses, unfortunately I have just seen a couple of his snaps with manual lens, but trust me the ones he has taken are beautiful. The build quality of old lens is a world of difference, when you are out shooting a lot, lens may take some beating, and the last thing you want is your plastic lens cracking up. Most of the pre 1990's lens were full metal, heavy beasts
As I mentioned before there is a huge IQ difference between a 50mm f1.8 (5k for Canon), and 50mm f1.4(24k for Canon). The latter is much sharper wide open, and has a beautiful creamy bokeh. In addition at 200mm a 18-200 at 200mm is not that different from a P&S IQ wise, now compare this to a 70-200 f2.8 lens (different price points here too, Canon L glass is 1.4 lakhs, while Tamron is for 40k) there is a world of difference in the sharpness levels, and not too mention the f-stop advantage which translates into a nice bokeh as well as shutter speed advantage.
Like some guy who always says to me, its better to save up for a good lens then buying cheaper ones.
Oh, and there is the whole beautiful world of film cameras, and 50 year old German lens
This guy who I know through weekend shooting has a 50 year old Hasselblad medium format film camera (medium format would roughly translate to 110 mega-pixels in digital parlance). I always thought what was a big deal on Hasselblad, and film SLR's but have a look at his photo-stream with square-composition images to get a general idea of pre-Carl Zeiss era of German made lenses:
http://www.flickr.com/photos/smz/