First, I'd like to point out that hash power in Bitcoin can indeed be regarded as voting power, but only about the part that is absolutely necessary. Bitcoin is generally a zero-trust system, which means all data received from the network is considered untrusted and verified. Rules like rate of currency introduction, not allowing a coin to be spent twice, requirement of valid signatures, ... are never voted about. Even a 51% of mining power cannot change these rules, as they would only get themselves ignored by the rest of the network.
The one thing they vote about is the ordering of otherwise valid transactions. This is necessary as physics imposes minimum times for communication across the globe, so in case there are two attempts to spend the same coin, the whole world cannot be expected to agree about which was first.
That said, the choice for using "one CPU per vote" was probably indeed made without considering the evolution to GPUs, FPGAs and ASICs. Originally, Satoshi envisioned every full node on the network to be a miner, and even asked to avoid the arms race to more efficient mining hardware as long as possible.
Still, I believe assigning votes to computational power (proof of work) makes sense. It may not favor equality (those with better hardware get more), but it is fair (everyone can invest in hardware and reap the rewards). Except for systems which depend on data in the system itself (proof of stake, proof of activity), I don't know anything that is as impossible to fake or circumvent as proof-of-work.