Disclaimer: this is my opinion and not a full-fledged recommendation for you personally:

Honestly, IMO, if you are starting small, just go with a diversified portfolio of big blue chip companies. A balanced asset mix would be a good place to start (50-60% stocks, 40-50% bonds) just to get your feet wet. As an FYI though, Buffet advocates 90% stocks, 10% cash (something to think about when you get more comfortable).

To me, a balanced portfolio is pension style investing (look up the asset mix of a few pension plans). This will allow you to still experience markets ups and downs without watching your portfolio go up and down as if it were on a roller coaster. Good luck.

PS- the US market is the largest and most diversified in the world. Don't underestimate your ability to diversify within your own borders. Most large US companies are multi-nationals anyway.