I bought my Z used, so I missed the depreciation hit. Of course, the downside sometimes to buying used is that you inherit some of the issues that made the original owner get rid of it in the first place. I got lucky with mine; car was in very good shape, and it came with a set of FI LTHs and a Takeda cold air intake already installed.
The tires were somewhat low however. I managed to get another year out of them before they finally wore out. Spent about $1200 to put a set of Michelin A/S3 on it. That's the only additional expense I've had in the 2 years or so that I've owned it.
Ironically, my insurance went down when I got my Z. Through State Farm, I was paying $130/mo on an 07 VERSA! Now I'm down to $98/mo (full coverage with rental). Lesson learned there, talk to your insurance agent every couple of years to see if they can bring your rates down. If not, start to look at other companies. Insurance companies love it when people sit on the same policy forever. Gives them an excuse to keep you with a higher rate.