Concerning RUP being obsolete and RUP v.s. agile methods:
I personally feel that the UP can be as agile as you want it to - after all, it is not a software development process but a software development process framework. Put simply, it means that you have a toolbox from which you can choose the tools appropriate for the mission you are embarking on. This can be an advantage, but also means some additional work (the choosing of tools) compared to a fixed development process.
If you are in a smaller team doing smaller projects, UP may be unnecessary large - something like Scrum may be more suitable.