The 23% VAT tax doesn't apply to all products, legal services are exempt from the VAT. Also, what does the VAT have to do with corporate tax, it's a consumption tax. Also, the corporate tax is falling by 1% a year to 20% by 2015. Germany, the UK, France and Australia all have comparable or higher rates of tax in the top tax bracket, yet none of those countries are falling apart at the same level Greece is. France, the UK and Australia all have higher rates of corporate tax.
As for the US and the Euro, the AUD is above parity with the USD. This is in part due to China and their huge imports, and the rate has been rising since the 2000s, but it shot up after 2008-09. IMHO, the best currency to invest in for the mid-long term would be the Yuan.
As for the prime rate being 30%, where did you get that number? I can't find any country with it above 10%, not even the 'socialist' Spain, Canada and Scandinavia (not a country, I know), and I can't find the prime rate for Greece. However, this site (http://www.tradingeconomics.com/greece/risk-premium-on-lending-prime-rate-minus-treasury-bill-rate-percent-wb-data.html) shows the prime rate for Greece between 1974 and 2004. Notice that it was falling during the time the PASOK was in power (late 1980s and early 2000s).