Well, vintage is easy - if you're going to get just one, you have to get a Primero. References range from around $2000 to $7000, so that 'll leave you anywhere from $3000 to $8000 to play with. I'd suggest an A 385 for the characteristic trapezoidal case and a graded-fume dial that gets better and better the more you wear it. It's completely underappreciated, so you can get a nice one for under $3K.
The new purchase is actually the more interesting. I see the options as follows
1. Zenith Striking 10th - this is the watch that relaunched the manufacture after the years of excess and eccentricity under Thierry Nataf.
2. Zenith 36000 VPH - this is the modern Primero chronograph (new one's on the left)
3. Zenith Winsor annual calendar - Primero + annual calendar
You'll probably have to shop a bit to get a good price to make it under your budget, but it is very doable. For example, Striking 10ths are starting to hit the secondary market in the $6K range. 36000VPH are still less.
Gratuitous shot of Thierry Nataf at one of his bizarro product release bashes in Dubai: