and a war welcome to the forum!
There are three main parameters for memory cards:
- size/storage capacity
- speed of data transfer
- reliability of performance
On size, you have to decide how many eggs you want to put in the same basket. Some like to have several cards, to spread the risk of malfunction. Others like biiig ones so they can shoot with abandon for hours and hours.
Speed gives you the possibility of longer bursts - but this is also limited by the buffer in your camera. A high speed card can only take the data as fast as the camera can deliver it. For the camera you have in mind, any contemporary card would do. No need to go for the fastest of the lot.
Of course there is the off-laoding of the card to your computer, which to me is less important, but you may feel different.
Reliability; well statistically they don't go breaking all the time. But it has happened to me once...at the worst possible time. My oldest sons graduation party...shot 850 pictures and lost them all because the card died on me. I will never buy no-name and marginal brands again.
Your camera will use SD cards I believe. 4GB cards seems to be the sweet spot these days, in terms of price and performance. It will give you probably around 500+ images at highest quality+size JPEG files. Less for RAW files and if you shoot JPEG+RAW even less.