It's a laptop running 1 GHz 1GB of RAM and Vista using 256kb/s connection. Slow as computers go. I noticed it was fast at the beginning and got slower as it added more blocks. It was loading hundreds of blocks a second at first. Now, it takes two seconds per block.
Ya, that's not suitable hardware for running Vista itself, nonetheless the bitcoin-qt for pulling a full blockchain. Even once it is caught up the blockchain verification will make the system appear non-responsive. It technically can work, it will just be very slow.
I do feel that this is one aspect of bitcoins that isn't going to scale too well in the future as the block history keeps growing, and won't be compatible with mobile computing.
End users don't need to run the full blockchain. Multibit is an SPV client , and Bitcoin Wallet for Android is an SPV client for mobile. These pull block headers only on initial sync.
And for those who do need the full blockchain:
An upcoming release of the Bitcoin.org client will do a much better job at this but it is not even to the testing phase yet [Edit: just reached the "test-if you dare" phase] so that shouldn't be something you want to wait on.
