I have the same budget constraint and want to upgrade to some L's
I shoot mostly landscapes (65%), but increasingly more urban and people shots (20%) with some indoor parties / weddings / etc. (15%).
Based on my research here and the opinions and testimonials of many, the lenses that fit my shooting needs best will be:
24-70 2.8 - New walkaround lens. People I spoke to tell me this stays on their camera 95% of the time (I like that - less dust on the sensor!)
& (1) of the lenses below
70-200 f4
70-200 f4 IS
70-200 f2.8
70-200 f2.8 IS
If I decide on the 70-200 2.8 IS, that really obliterates my budget, and I would only be able to get that lens.
The 70-200 f4 is a great value, but I fear its usefulness would be mostly outdoors, and I would find myself selling it in the not to distant future for a 70-200 f 2.8.
That leaves the 70-200 f2.8 Non-IS and the 70-200 f4 IS. Canon priced these two very close together, and if my goal is to be able to shoot in lower light situations when they come up (not a majority of the time) or indoors and I am not shooting fast moving objects, the f4 IS may be perfect for me.
If I have overlooked anything in my "thinking out loud" notes above, please let me know. I have been trying to figure out which ones to get, and my eyes are well glazed over at this time... Your opinions and thoughts welcome!
Bryan