I agree with those who are saying it depends on the dosage if inflation is good or bad. There will always be inflation or deflation as long as there is an imbalance of money supply to good and services (I believe there always will be even if we get rid of central banks, as long as the thing we use for money does not grow in exact proportion to goods and services, which I'm not sure is possible).
Inflation will always affect people in different ways, for example if I am a business owner and can pass the cost of inflation on to consumers this is beneficial to me as my revenue is inflation proof, and in some sense my purchasing power increases as whilst inflation decreases the purchasing power of everybody else, it does not affect me. If I own assets which grow with inflation, fantastic, if I own debt maybe not so much.
The real problem is when inflation/deflation gets out of hand because, as Drew has mentioned, that's when the inequality starts because the different ways inflation affects people as I mentioned above start to have a greater effect (i.e if I give people varying amounts of water, if the variance is only one or two cups, it is fine. If I start letting people die of thirst whilst waterboarding others then the effects start to really cause differences in outcome to people)