Wow, I love to see somebody else who likes to do more architectural modeling!!!
If you want a tip, go to the Alias Wavefront site and download the "ocean waves" shader. I don't know what I would do without it! If you take the time to tweak it, you can obtain so many different types of very cool looking water.
Also, if you were using the Maya renderer rather than Mental Ray, you may want to take a look at the Paint Effects and the great clouds you can get if you play around with it a bit.
I look forward to seing more!