Tax Efficient Investing

[Badger]

So I've been maxing out my Roth, and putting a decent chunk in my 401k. I'm getting to the point where money is piling up in my internet savings account that I feel I should be doing something else with.

Soon I plan to start putting money away in index funds and ETF's that I don't have to manage for the time being. I'm 25 and I feel that I've got much better things to do than study the stock market right now. I feel pretty confident that I have enough basic knowledge to start doing a good job of this myself (i.e. picking who I let manage it for me).

One thing I'd like to better understand before I do this is the tax implications of what I choose. Can you explain to me the basic ideas that I should be considering when making an investment.

This money will probably be sitting around for quite some time. The only thing I could see myself dipping into it for would be a home purchase, but even then a majority of what I'm saving is still in it for the long haul.

To clarify, I'm not asking for fund recommendations, there seems to be plenty of good information on that here. I'd like to clear up what tax implications I should be considering since this is a non-retirement account. Does this change at all if I end up donating a sizeable chunk of my investment?

Thanks so much for helping me out with my first real investment work.