I lasted 4 months with a Mk5 GTI. 9 months with an Ibiza FR TDI (mainly because of commuting) 11 months with the Clio 200, 3 months with the Scirocco (but it was a crap example) and I've had the Polo GTI for 5 months.
To be honest, as much as I'd love a Roccco/Golf R at the moment. My main reasons for wanting to change are a hankering for a T4 camper for holidays away with our 2 dogs and also an itch for an older car that I can modify the nuts off again. Like another Mk1/2 Golf.