The EHIC replaced the E111 in January 2006. It will cover you for emergency treatment whilst in EU and EEA countries plus it will cover you for treatment to a pre-existing condition. However, whilst emergency treatment (broken limbs, coming down with the lurgi etc) will be provided free, pre-existing conditions (such as heart disease, diabetes etc) may be charged for. You can then claim this back from the NHS when you return BUT only up to what it woul have cost in UK. For example, if you need insulin for diabetes and it costs £25, you can claim the difference in UK between the prescription fee (£6.75????) and the £25.00. If a doctor charges you £50 for a consultation, you can't claim anything back as it would cost £50 in UK even though you get it free in UK.
(Hope that makes sense) Basically it is saying you get free emergency treatment but be prepared to pay if you have an existing condition.
Most annual travel insurance policies to Europe are only valid for visits up to 30 or 45 days so be careful. You can take out single trip insurance for up to a year which will, obviously, cost more.
Direct Travel (direct-travel.co.uk) is very good. We pay £46 a year which covers both of us for as many trips as we like in a year but is limited to 30 days at a time. Also note that travel insurance policies don't cover pre-existing conditions.
The EHIC should cover you for anything that crops up whilst you are there but, as More says, too many trips to the A&E may get questioned. Also be careful when applying for the EHIC and only use the official website where it is free. Some sites say they can get the EHIC for a fee but it is very easy to get one without paying. A quick form on the EHIC site and the cards arrived 2 days later.