iPad mini 2: Retina display. From £239 with 16GB.
iPad mini 3: Retina as well. From £319 with 16GB.
iPad Air: Retina. From £319 with 16GB.
iPad Air 2: Retina. From £399 with 16GB.
In other words, all four iPads have Retina displays (but none have Retina HD). Apple discontinued its only remaining non-Retina iPad - the iPad mini 1 - earlier in 2015, although you may be able to find a second-hand or refurbished model.
As with the iPads, there are no non-Retina options here: all iPhones currently available have at least Retina displays. The concept was introduced with the iPhone 4, and was also present on the iPhone 4s and iPhone 5.
Of the four iPhone models currently available, the iPhone 5s (Apple Shop link) and iPhone 5c (Apple Shop link) both have Retina displays, whereas the iPhone 6 and iPhone 6 Plus (Apple Shop link for both models) both have Retina HD displays.
12in MacBook: Retina (from £1,049).
MacBook Pro laptops
13in MacBook Pro: non-Retina (from £899).
13in MacBook Pro with Retina display: Retina (from £999).
15in MacBook Pro with Retina display: Retina (from £1,599).
The non-Retina MacBook Pro is £100 cheaper than its approximate Retina equivalent, but in this case the comparison is difficult: the non-Retina model is much older and has numerous differences other than the displays. (It has a hard drive rather than flash storage, for instance.)
MacBook Air laptops
All of Apple's MacBook Air laptops are non-Retina. But there is a persistent rumour that a Retina MacBook Air will launch in the near future.
21in iMac: non-Retina (from £899).
27in iMac: non-Retina (from £1,449).
27in iMac with Retina 5K display: Retina (the clue's in the name...). From £1,599.
Adding a Retina display to your iMac adds £150 to your bill.
Are the Retina and Retina HD displays worth the extra money?
Let's start with plain old Retina.
For certain tasks, Retina screens are absolutely worth the money (although by this point you may well find that non-Retina alternatives are getting thin on the ground). If you're going to use your iPad mini for reading ebooks, for instance, you'll really benefit from a sharper screen. And if you edit photos on your laptop, they'll look a lot better in Retina form.
Bear in mind, too, that the price differences above don't just reflect the inclusion of a Retina display. The iPad mini 2 has a more powerful processor that the non-Retina iPad mini 1, for example, so it's much more future-proofed for handling apps and games in the future. Of course, the original iPad mini is no longer available from Apple, so you may find when searching for a second-hand or refurbished model that it's therefore cheaper still, and may tempt you for that reason.
Sign up for MIS Asia eNewsletters.