I am out of the income range for a traditional/roth IRA and invest a little bit in my company's ESPP program (10% discount). What other efficient investing options should I consider?
You can still contribute to an IRA. If you make too much to deduct your IRA contributions, you can make a non-deductible contribution then turn around and convert all of your IRAs into a Roth using a Roth conversion. If you have some other tax-deducted IRAs it might cause a big tax to you, so make sure you consult with a good advisor and/or tax accountant first. You can always put an annuity "Wrapper" on your investments if you are concerned about taxes now and want to defer more of your savings. Other than that, just open an individual investment account. Work with a good advisor to help you get tax efficient funds. Every situation is different and I can't give exact advice for you without knowing more about your full situation but I hope these give you some good ideas of where to start.
Brent mentioned great points, as well as you can look into tax-free investments that will generate you income tax-free on the State or Federal Level, and possibly even both. Speak to an Advisor and explain to him your goals, where you are right now in regards to your deferrals, where you want to be, and find out the possibility to get there.
Does your company offer a 457 plan for highly compensated employees? Some do, and it may not be a benefit they promote company-wide due to the fact that only some employees qualify.
Hopefully you have a CPA / accountant and their tax strategies should be discussed with your investment advisor, who can help you make investment decisions with tax-advantaged investing in mind. Your advisor may recommend a specific type of account, the type of investment vehicle to invest in and the timing of transactions, and those decisions can all have tax implications.
If you don't currently have an investment advisor, you should be able to find one with the knowledge to assist you with tax-advantaged investing strategies.
Roth IRA if you don't make too much money.