It's impossible to recommend a filter without knowing what's in the water. If your water is soft enough, those simple inexpensive charcoal filters will be fine. Once the hardness and alkalinity get above 50 mg/L as CaCO3 (appx 3 grains per gallon) then you have water that may require you to descale, and therefore may benefit from a softening or decarbonizing filter if you are looking to descale the machine very infrequently or not at all.
If you use a good bottled water, you can use no filter at all in the machine. But be careful in choosing your bottled water - Deer Park spring water is an example of a water from a variety of sources, and their water report ( here
) indicates that any given bottle might be overly soft, or it might be moderately hard and scale-prone. I'd steer clear of it for that reason.
Crystal Geyser also comes from different sources, but you can look at the fine print on any bottle and check the source. Here's a post with a handy table showing all of CG's sources and numbers: Blonding too fast. Profitec 700.