Tell them that the old way (their choice to do full + increm) was a very viable, dependable option. But with today's intensive growth scale of data retention, and need to provide redunancy for business continuity, we have a better way of doing it. It will not only reduce the unecessary need for redundant data (versions of files re-backed up with the Full), but with new versions of TSM (6.x) it will even provide de-duplication to your diskpool.
Also throw in the executive dazzle words, like encryption, hierarchical storage management, data integrity, bare-metal restores, etc. Stay away from things like backup windows and stuff like that; IMHO they could care less if you struggle with getting your servers backed up overnight. They want to know what is the best (cheapest) way to backup data correctly. If you use VM's note the way that Tivoli licenses the VM's per host with their PVU's (Processor Value Units). You get more bang for your buck there.
Remember to use flashy items for visual aides, smile and laugh at strange times (waiting for them to nervously laugh as well while not knowing why), and use Yogi Berra quotes whenever possible. You will do fine.
