Another one to add to Philip's cracking starter list and consider is Phal. bastianii.
This one (according to what I have been told) is also another good species for beginners, and similarly to P. equestris has a habit of producing keikis.
It must be noted that it is sometimes confused with P. mariae.
Here's a link to a good picture of one.
http://www.dustindorton.com/orchids2...s/DSC_8737.jpg
and one for the info
Phalaenopsis bastianii - Orchids Wiki
But I must admit you can't really go that wrong with a P. equestris. Unless your growing conditions really aren't suitable. They also come in a good selection of variants.
As for one plant being harder to grow than another, I think that depends on a few things, like Research and the Growing Conditions which you can provide. Species, Hybrid or Noid, if you don't treat it right it just wont do well.