What tax/es should a country use to collect revenue?

[True Federalist (진정한 연방 주의자)]

I prefer a real estate tax over a land value tax.  This is for two reasons.  First, the idea that we should encourage construction by not taxing improvements strikes me as placing an unhealthy emphasis upon economic activity as the sole positive good in a society.  Second, I feel the need for many government services such as police and fire services is more likely to be proportionate to real estate values than to land values alone.  Hence the variation in rates needed to pay for the desired level of service between different areas should be lower with a real estate tax than with a land value tax.

Next, Pigovian taxes upon specific products whose consumption we wish to reduce.  They are generally fairly easy to collect and have useful secondary effects, provided they are not set so high as to unduly encourage criminal evasion of the tax.  Alcohol, tobacco, marijuana, fossil fuels, lead, and more can all be subjected to them.  Gambling and prostitution as well, but the ease with which independent operators can enter into these fields suggests that they should be limited to casinos and brothels (including the virtual internet kind).

Third, short-term capital gains (ideally long-term capital gains, i.e., taking ten or more years to be realized, should not be taxed), with the shorter the term, the higher the tax rate.

Next comes user fees disguised as taxes for ease of collection.  For example, sewer rates based on water consumption because the incoming is easier to measure than the outgoing.  If we do start to see a significant decline in internal combustion engine powered vehicles as a share of the motor vehicle fleet, we'll need to shift away from motor fuel taxes to other taxes such as odometer taxes or tire taxes.  (Altho tire taxes alone cannot hope to raise anything close to what motor fuel taxes do now without being so high as to make tire theft very tempting.  Still, it would be a way for bicyclists to contribute to the cost of bike lanes.)

Then comes death taxes.  These taxes are intended to serve a particular function, to prevent the concentration of wealth, and as such as social engineering at its most class conscious.  The confiscatory rates they were once at were too high, and to some extent still are high.  They should be no more than the level of taxes on ordinary income.  If levied at all, I'd prefer to see them levied as inheritance taxes rather than estate taxes.  (The difference is that if there are exemptions as there should be, then the more inheritors of an estate, the greater the exemption.)  I'd like to see spouses exempt, save that if they remarry, then the new spouse would be subject to an inheritance tax on anything that came from the estate of the guy or gal he replaced.  The trust and family business problems can be dealt with by having such estate assets subject to an inheritance tax only upon the receipt of funds from the trust or business.

Last but not least we come to generic taxes on gross-receipts and personal income (sans capital gains, see above).  I'd prefer eliminating all so-called corporate income taxes and sales taxes by replacing them with gross-receipts taxes.  It is far more difficult to use accounting gimmicks to avoid taxes on gross-receipts than on taxes on gross-receipts without engaging in outright tax fraud.  Sales taxes levied only on the "final" consumer invite fraud as to who a final consumer is.

If the rates are equal on gross-receipts and wage income, then there is no reason for taxing dividends as income (save as part of an inheritance tax, see above), but if the gross-receipts tax is lower, or there are exemptions on gross-receipts tax not available for personal income tax, then I would support a dividend tax to prevent the establishment of companies for the sole purpose of tax management.

The sole virtue of the complexity of a VAT is that in comparison to a straight up gross-receipts tax, a gross-receipts tax encourages vertical integration of businesses.  However, vertically integrated businesses have difficulties in efficiently managing their supply chains, so I'm not certain it's a big problem.  It certainly would not be a major problem for the retail industry, tho you'd see a bigger use of the consignment method of doing business.  (I.e., that cottage cheese you bought at the supermarket was actually owned by the dairy and not the store until you took it to the checkout.)

[True Federalist (진정한 연방 주의자)]

I'll add to this discussion when I have more time, but one point I'd like to make:

It can actually increase economic activity if structured as a land value tax(calculated based on the value of the land itself while excluding the value of improvements made to it(ie. a house)), because it strongly penalizes underutilization of land.

While I suppose it's not really something to worry about in today's economy, couldn't this potentially lead to rather significant real estate speculation and thus risk creating a new housing bubble?

Not really.  Assuming a land value tax is structured to generate the same revenue as a real property tax does, then it should have no significant effect on a speculation based on a general rise in property values.

More significant is the effects going to a land value tax would have on land use.  In urban residential and commercial areas, a land value tax promotes the building of multi-user structures in the high-value core since that reduces the per user tax.  Apartment buildings and multistory malls would be more common.  The tax advantages of living in the exurbs instead of the suburbs would be greater as well.  Gotham likely has a land value tax, as it helps explain why Gotham City has so many skyscrapers and why stately Wayne Manor is 14 miles from it.