York are OK. Try to get the longer ones. make sure there is no stupid plastic thing in the middle where you grip the dumbell. if you get rubber coated plates they will cost more and smell, but, will be quieter if you workout at weird hours in a house full of sleepers. otherwise go for metal plates.
you can put pvc pipe over the centre of the dumbell and hence make a thicker dumbell IF you buy screw-lock dumbells you can screw the plates tightly onto the pvc pipe. it really is a good idea. a 2" pipe or 3" pipe thick handle dumbell is great.
The 18" long ones are better than 16" because you can load them with a lot of plates as you get stronger.. But the 16" ones are more compact so that can be good too.
Try to buy small diameter plates. Instead of two 5kg plates get four 2.5kg plates of smaller diameter. The larger diameter means the dumbell is further from your body and that can cause some injury or at least it gets in the way.
note with the pvc pipe in the middle you can extend the grip area to allow two handed grip of the dumbell which can be useful for weird old-style exercises, or, when grabbing the dumbell at one side so to create rotational forces.
I've become fond of York brand they are cheap, strong, readily available, the screw locks have rubber on them to keep 'em quieter.
note dumbells can do most things and will last a lifetime.
hope this helps.