[kv968]

I agree with the others, your best bet is to max out the pre-tax up to the 25% limit. The advantage of contributing post-tax is that if you think you'll be in a higher tax bracket than you are now when you start taking withdrawls, you can pay the lower tax now instead of the higher tax later. However, when you start taking the withdrawls in retirement, most likely you're income level will be the same or less than it is now since you won't be working as much, if at all. And using pre-tax money means you're actually contributing more than if you did post-tax. For example, if you're in the 25% tax bracket and wanted to contribute 10% of your gross earnings, you would have to contribute about 13% of your post-tax money to equal the 10% of the pre-tax.

As far as your excess of the 25% limit, if your options in the 401k are good then keep contributing there post-tax. If they aren't that great, then you could use a taxable account. Just make sure to only hold tax-efficient funds, such as index funds, in it.