I bought a 14 month old 1.8 petrol Titanium in February. I went for petrol as I also do mainly short journeys and the diesels with particulate filters can become clogged very easily. Also the petrol was over £1000 cheaper than the diesel equivalent - and given i do less than 8000 miles a year, the higher fuel consumption of the petrol is less of an issue. The balance of the Ford warrenty is valid at any Ford dealer.
The 1.8 petrol engine has been around a while so I think it's quite reliable. It isn't very efficient though, expect 20-25mpg round town, 35mpg on a long run. The diesels are quite good, the 2ltr had plenty of torque and power. You can expect 10mpg more out of the diesels, if not more.
If you get a 1.8 petrol with a 5 speed gearbox, you might find ( as I do) that you'd like a 6th gear like in some of the diesels (I don't know if you can get a 6 speed on a petrol??)
I've got the sportpack 3 with lowered suspension and 18" wheels and it handles really well, but can be crashy on bad roads. I might look to swap to 17" wheels soon.
2008 1.8FF Titanium, Nav Pack, Sport Pack 3, Panther Black