my system has 6GB or RAM in it, and is going on 3 years old now. it wasn't even considered a high end system at that time. so to say most system you come across only have 2GB seems a bit weird to me.

i would certainly say a laptop with on 2GB of RAM is going to have some pretty obvious issues with a lot of modern programs, especially if you're running 64bit.

and on topic of this thread, if you';re after something cheap which will have options for upgrading in the future.. a laptop is not the way to go. As Coda said a lot of cheap laptops have very limited options for swapping out parts. generally you have to buy a new laptop to upgrade.
a desktop on the other hand will always have the option for upgrading, only restricted by the size of your case, how many ports the motherboard has etc.