I see people talking about 0.05% expense ratios, presumably meaning the Vanguard S&P 500 fund. Vanguard advertises an average expense ratio of 0.19%. Sounds great. But the index funds from iShares, DB x-Trackers and Lyxor I see in my bank's funds DB are much more expensive, mostly round 0.5% (even ETFs). And Vanguard is apparently only available to US residents.
So which are the cheapest options available in the EU? I'm looking for both specific funds and general information - for example, Vanguard also lists a 0.05% ratio for their S&P 500 ETF - can I simply by that on an exchange? Would it cause any problems?