Well i'm currently working with ArcHydro, and I often thought to myself since "why couldn't I have done real world stuff like this while I was a uni?" we got given boring mundane scenarios and projects. I think the step you're taking is good and get some exposure to all you can while you can.
How about getting stuck into something like ArcHydro?? You already have the software and you can download ArcHydro from the ESRI support site, and the states has all the data you need to get up and running avaliable for free.
David Maidment has some good pracs on his University of Texas website
David's site here. This will give you exposure to a different specialised extension, while doing some network anaylsis, learning how to apply a schema to a data set, and if you are willing to go far enough even introducing you to the exciting realm of time series data!!
Best of luck
Andrew