My idea is to split personal income taxes into two categories - earned and unearned. Earned is salaries, piece work, etc... IE you 'did' something to earn that money. Unearned is capital gains, interest, dividends, and such, money earned from the simple fact that you 'owned' something. Your first ~$10k of income in either category is taxed at 0%, after that it's tiered in parallel like the current system. Assuming an average return rate of 5%, that's $200k in investments before you start having to pay taxes on the return, which is a good amount for emergencies, college, early retirement, and what not.
That's pretty much what the UK has already. A certain amount of your annual income is tax free (about £8000 this year) after which income above that is taxed at 20% up to the next tier, above which income is taxed at 40%.
Capital gains are taxed at 18% or 28% depending on your total income, with the first £10000 in a financial year tax free. Dividend income is taxed at at the income tax rate, with a deduction to account for corporation tax (so you'd only pay income tax on the dividend if you're taxed at 40%). Bank interest is also taxed at your income tax rate (20% automatically witheld, if you're a higher rate taxpayer you declare the remaining tax on your tax return). Stock held within a tax-free account (pension, ISA) attracts no capital gains tax and no additional tax on dividends.
Obviously, if the corporation tax is abolished somebody is going to have to make up that tax revenue, which ends up being the tax-paying citizens, so the tax rate for us is only going to go up. And bear in mind that similarly to large corporations, many high net worth individuals take advantage of loopholes in the tax code to minimize their tax bill. It's not a sense of injustice that makes people go into the 'shady' areas of the law to avoid tax, it's greed.