Don't worry about the difference between 1.0 and 1.1, the current version is 2.0, there is still not any tangible benefits to 2.0 unless you run Quad GPU setups.
PCI-E 3.0 will bring a bit more to the table than 2.0 did, which mainly just increased bandwidth.
pci/e 2.0 has double the bandwidth of 1 it can transport double tha data of 1.
running a pci/e 2 card in a pci/e 1 mobo will half the total bandwidth the card can use with the motherboard to access the cpu and ram.
It has been said that as they still cannot fully utilise the pci/e 1.1 bus yet that 2 is pointless , but a i can tell you from experiance that upgrading from a 1.0 mobo to a 2.0 mobo (my friend already had a pci/e 2 card) gave him a 10fps boost in Crysis and Far cry 2. These are the only two games we could benchmark reliably but i dont think it was just a glitch , the mobo chipset was also differant (obviously it was pci/e 2 compatible )
SK