I would say that the thing I love to cut the most with my Silhouette is Heat Transfer Vinyl – it’s what you use to make your own shirts, and it’s super awesome!!
If I had to convince you of why you desperately need a Silhouette with just one project (which is hard, because it can do so many things!) I would use Heat Transfer Vinyl. Because I use it all the time – see:
This month Silhouette is running a promotion that includes a bundle of heat transfer vinyl: