I think $14k for a 4-5 year old Matrix is really pushing it (even though it is the mid-range model and it has low miles), and I doubt you'd be able to get it for much less than $13k. For maybe $2-3k more, you can get a completely new 2010 model. One thing to consider is that the prices you're seeing on new cars is MSRP, but you're usually able to get them for very close to (or even below) invoice, which is roughly 10% less than the MSRP. So a $17.5k (including destination) Matrix is really closer to $16.5k. If you include the cash incentives most manufacturers are running, you can shave off an additional $500 to $1000 (which may be combined with low APR financing).
But the whole "X is just a little more than Y" can definitely lead to a very slippery slope for these kinds of purchases, so I can understand if you don't want to. For used cars, I just did a quick search on cars.com and found a lot of what I would consider to be better deals. Anywhere from $0 to $1k more for 2009 models with 0-10k more miles. The Matrix went through a model change in 2009, so both the inside and outside are different from your listed 2006 model.
Here are my results. It's obviously a different area, but yours shouldn't be too different:
http://www.cars.com/for-sale/searchr...MENT&pgId=2102