Rich,
Ive worked at Nissan until recently, only real issues with the Note is Lambda sensors play up occasionally, the 1.5 dci engines are prone for throwing rods through the block (renault engine), but the 1.4 and 1.6 16v engines are reliable.
Try both the 1.4 and 1.6 engine, the bigger one is about the same on fuel but makes the car seem better at motorway work.
The only other issue, is cracking of the chassis leg round the gearbox mount, ive seen two 07 models be repaired in the last 6 months, under warranty of course. Not sure if its a common issue, but worth checking.
Make sure you get a decent spec, the S models (or later Visia) are bobby basic, no a/c as standard, shit radio, wheel trims. Most folks go for the SE (or later Accenta) with 15" alloys, CD, Trip Computer, A/C, the top of the tree was the SVE (or now Tekna), with half leather, cruise, 6cd, privacy glass and 16" alloys.
Dont rule out the autos either, they drive really well, plus any self respecting pensioner will always want one.
Hope this helps fella