The 17-40f4L is also a very nice lens, focuses extremely fast, and great for candids - if you plan to go FF, then upgrading is a good idea, else stick to the Tamron.
Of the 70-200 lenses whether f4 or f2.8, all are very sharp, some sharper than others. For the f4 version, the IS is the better lens, while for the f2.8, the latest greatest and also most expensive mark II is better. The f2.8s are all generally heavy so be prepared.
While not all primes have great bokeh, if you are looking at this price range, also consider lenses like the 85L, Sigma 85, 135L, and the Sigma 150macro - all of which have good bokeh and are really excellent for portraits. Whether better than the 70-200, you be the judge since this is very subjective. You can also consider the Sigma 50, which is has nice bokeh too. Of course if you want flexibility, then your only choice is the zoom.
Last edited by Kenneth67C; 10th June 2011 at 10:43 AM.
An artist who realizes there is a supreme force and works gladly as an apprentice under heaven.