This one is easy. By this point, you have no debt payments except for maybe your house. Taking 15% off the top should be easy enough to accomplish.

The first big question is where to stash it all.

Well, if your employer offers a Roth 401(k), that’d be your best bet to get started. If you have adequate control over the investments in the account, you should look at maxxing out your contributions to the Roth 401(k) account. If you’re choices are limited, then contributing to the Roth 401(k) up to any employer match is your best bet.

If your employer does not offer the Roth version of the 401(k), you will still want to contribute into a traditional 401(k) up to the employer match. Or, if your employer offers a 403(b) or TSP, you’ll want to contribute into those programs.

After maxxing out your 401(k) or other pre-tax retirement account, you’ll want to try putting the rest into a Roth IRA. With Roth IRA accounts, you may be, depending on income limits, allowed to contribute up to $5,000 per person (as of 2008). Income limits for 2008 are up to $101,000 for single filers and $159,000 for married filers.

If, after contributing to your employer’s retirement account and Roth IRA, you are still not up to 15%, you will want to go back to your employer’s retirement account and contribute enough to get you to 15%.

For more information: There’s a great article on Wikipedia that compares the different IRA and 401(k) types: 401(k) IRA matrix.

Now that you have your accounts setup and 15% of your income going in, you need to figure out how to invest it.

Dave’s investment philosophy is quite simple:

25% into each of these four types of [mutual] funds:

• Growth
• Growth & Income
• Aggressive Growth
• International

And, to expand on what Dave says, I’m going to point you to the folks over at Merriman Berkman Next and their Merriman Model ETF Portfolios. Dave’s biggest requirement for financial advisers is that they have “the heart of a teacher.” Well, Paul Merriman and the guys fit that reqirement. They have a free weekly podcast called Sound Investing that offers great advice and learning. In addition, Merriman Berkman Next offers free educational workshops.