Well, we tell our clients... lol jk ha haa
I would say that a Roth is ONE way to go about it, but there are many factors involved in this decision making. Of course the common knowledge of diversification still stands. You want to have risky and less risky investments in your portfolio. Some of the less risky ones could have dividend paying stocks or even bonds. These vehicles should be used in the Roth IRA and any other taxe deferred account because you don't pay taxes EVERY YEAR on the dividends.
If you're unsure of the exact funds or stocks to buy, I would go with an index type fund of the broader market until you learn some of the other choices that are offered. These funds have outperformed more than roughly 80% of the other managed funds around. Vangaurd Group is a very good source for these index funds with VERY low expense ratios to manage your accounts. You may want to split up these index funds into an S&P 500 and small/mid cap or the Wilshire 5000 index fund of some kind. I would go about 75% in that and about 25% in an international fund. If these are too risky for you, and only YOU can decide, you may want an income producing fund like a Ginnie mae (sp?) fund GNMA This is also provided from the Vangaurd Group family of funds which I recommend, again, for their very low expense ratio. This GNMA fund has payed out about 9% last year and about 7-7.5 for the last 5 and 10 years with a lot less risk than the market. THERE IS STILL RISK in these funds but it is less than just buying stocks.
The example of the GNMA fund would be great for an IRA because it would not be taxed constantly while you're getting payed every year from them and would grow that much faster tax deferred or tax free as in the case of a Roth.
Also another thing to consider. Will you be in a higher tax bracket when you retire? You may want to look into the benefits of the Roth opposed to the tax savings of a traditional IRA to make your decision. You can NOT deduct a Roth IRA's contributions for the benefit of taking all the money out tax free upon retirement. If you choose a traditional IRA, then you can deduct the cost NOW on your taxes and use that money for yourself or more investing..or whatever, but must pay taxes on the money taken out at retirement. So it's a decision you must make when calculating your tax bracket now and in retirement. The bottom line just fyi is most people will benefit from choosing the Roth, depending on age etc...
Sorry for the long post, I DID leave stuff out as to not sound too geeky. I also proposed the Vangaurd Group to answer one of your questions as to not totally deviate from your original post.
If you have a little patience and don't mind reading. I HIGHLY recommend Bob Brinker Market Timer newsletter. He has been spot on for many many years and gives very solid advice in regards to the exact mutual funds to buy (and sell when the time comes) He also has a "passive" portfolio for the index funds which I outlined if you're not into reading and keeping up with everything. good luck!