hmmm... i was wondering if you are a CS eng guy what hardware are you thinking at!
Anyways in my final yr i made a Nokia PC suite type software which will work with all mobiles and gave some features which are still not available with nokia PC suite..
That was too cool! and was made in .net
Also in my 2nd yr i created one more project just to waste time in my vacation
.. It was a administrative tool but web based(ASP.net) with lots of registry tricks with very good user interface. It also had a special security feature which would allow only the administrative user of any computer to open the site on any computer hence avoiding miss use.
Let me know if you need any help!
One thing from my experience.. what ever you make make the UI superb.. because those externals who come to see the project are 80% times dont know anything.. and a nice interface can make them happy!
All the best!