Whoa! Watch out for that bandwagon, its gonna break with so many people jumping on it without clue

If only everything that was shouted louder by more voices was true!
I am telling you this right now as fact. If you get a slower mem card it will take longer to store the images and can actually stop video recording from working correctly, any apps stored on it will slow down the phone. I am not saying the 4GB version is too slow (in fact its fine), I am referring to the many other generic brand cards out there. Its a not a N95 specific issue its a KNOWN issue in regards to mobile phones for years. Search the interwebs... its full of people complaining about such things.
The 4GB is perfectly fast enough, just avoid other manufacturers such as Integral, Transcend, Kingston etc...