As you can imagine this question has been answered more than once wilo.
Always get my oils from Opie Oils a trader on here & lots of other car forums too: http://www.350z-uk.com/forum/108-opie-oils/
You want a fully synthetic oil and personally (in my 03' Zed @85K miles+) I used to use 5W30 (as do most others) although I did change to a 5W40 after I had my Zed supercharged.
With yours being even higher mileage if you're unsure the best thing to do is ask the "Oilman" from Opie Oils that I linked above.
As for brands then there are loads to choose from with most being fairly similar (just as good as another imo). I've used Motul, Fuchs, Silkolene, Millers and others in the past which are tbh on the expensive side especially compared to own brands from Halfords or something but as I believe oil to be the life blood of any engine I don't mind spending an extra £20-£30 odd once a year for my oil change.
Some info here: http://www.350z-uk.com/topic/77-faq-what-engine-oil-should-i-use/