Optimal top marginal tax rate and corporate tax rate

[mileslunn]

In your country, what do you think the optimal top marginal tax rate is and what the optimal corporate tax rate should be.  If you have taxes at multiple levels, then give the breakdown for each so federal and state rate understanding they will vary at subnational levels, but otherwise what you think is the best level.  I don't think many on the left support 100% tax rates just as many on the right don't support 0% so its more what is the optimal rate and do you think it is too high or too low in your country.

I live in Canada so my ideal one would be as follows:

Top marginal rate would be 40-45%, ideally 40%, but could go as high as 45% if in a bad fiscal situation.  Federally it would be 25% to 30% and provincially it would be around 15%.  At this point federal top rate of 33% is too high while most provinces asides from Saskatchewan and Alberta are also too high.

Corporate tax rate would be 25% (maybe 20% if US drops it further as we need to stay competitive with them) with it being 15% federally and 10% provincially.  That means federally it is about right while provincially should drop 1-2% depending on the province.

For the US:

Top marginal rate of 35% once the budget is balanced but 35-40% while still in deficit at the federal level while top state tax rate of 4-7% depending on individual circumstances

Corporate tax rate of 20% federally at 4-5% at the state level.  So in sum US tax rates are about right but close several of the loopholes so government can get more revenue while keeping rates competitive.

For the UK

Keep top marginal rate at its current 45% until budget is balanced and then once balanced eliminate the additional rate so the top rate is 40% like it was under Thatcher, Major, and Blair.

Corporate tax rate: Keep it at its present 19%, that is already low enough so no reason to go even lower unless other EU members (yes I know Britain is leaving but still its main competitors) drop theirs to lower levels.  Otherwise as long as UK has the lowest corporate tax rate of the big five in Europe (Germany, France, Italy, Spain, and UK) they are fine.

Any thoughts?