Plextor is overpriced compared to their quality against the average drive. They're nothingspecial, despite their cost. So instead, you should get any decent brand with a proper price. Pioneer, LG and Samsung are strong contestants.
As for the interface, if you don't use the drive much - say, you only burn something once a week and then never use the drive - go for the USB/FW one. But if you keep it in regular use with mission-critical burns, definitely PATA or SATA to lower the chance of coasters. USB is very susceptible due to the way it works.