Is there much difference in speed between the 1.83Ghz & 2.0Ghz models of the Macbook Pro laptops?

I can get a good deal on a refurbished 1.83Ghz & would like to know whether it would be much slower than a 2.0ghz model.

FYI I plan on installing 2gigs or RAM into the 1.83Ghz if I was to purchase it.

Well, its .17ghz difference per core.
As long as you have decent ram, you are probably only talking about seconds off of rendering time. I've used both, and although there was a noticable difference, it was very slight.

If you can get a deal on a 1.83 then go for it.

What about things like starting up programs & general internet browsing/email? Is there any noticable difference there?...

Not that I found. They are both really fast! I love the new intel Mac's....

Just make sure the video card supports what you need. I think the ONLY difference is 128MB vs. 256MB, but double check the Dual-Link ability to run 30 inch monitors.