International in taxable is less straightforward that was mentioned above. Here's the brief +/- involved:
(+) foreign tax credit, which tends to be a small percentage of dividends
(-) for many years now, international has had +1% higher dividends (right now 2.9% int'l vs 1.9% U.S. total market)
(-) a lower percentage of international dividends are qualified (compared to U.S.), so you pay more tax on this part, also.
(-) you must file form 1116, and both H&R Block and TaxSlayer dump you into this form to fill it out on your own. No interview involved.
Back to OP's allocation question - take a look at tax-exempt bonds. If your tax bracket makes them worthwhile, it's a good idea to put them in taxable. That frees up more room in retirement accounts, and has minimal tax impact (when selling the bond / bond fund shares, you still pay capital gains, if any. Most of the gains from bonds are from income).