It is the nature of all businesses that there will at some stage be a skills shortage. This could mean that you will be called upon to perform tasks that aren’t normally part of your general duties. You will be tempted to use this as an opportunity to show off. Don’t. If you excel in this extra task, or even if you perform it remotely adequately, it will be added to your general duties, and you will remain doing it long after the skills shortage lengthens.
For this reason it is important to make the job seem harder than it really is, and make sure you let everyone know how difficult it is. This way, regardless of whether you succeed or fail, people will not only be impressed that you even undertook the task, but will also know not to ask the whiny guy to do it again.
When executing the task try to keep your name off any documentation that may arise. If any evidence exists that you have performed the task once you will always be referred to as an expert in that field. It is an extreme, but in some cases acceptable, measure to chase down anyone that can provide anecdotal corroboration to your involvement and cajole or even threaten them accordingly. Bribery is expensive but can be used as a last resort.
In all cases the best option is to avoid the task altogether. This can best be achieved by acting so busy on your current tasks that even the act of approaching your desk seems such an imposition on your time that it is not worth the hassle. Under the current climate this should not pose a problem.
Ahh, the whiny guy - he who makes the most noise does the least work - as Confucius never said.
My favourite of all working types is the "That's not in my job description" guy. It just paints a nice 'Never Going To Be Promoted' sign on their back for easy identification.
Saves a lot of hassle.