Setup Multi-Region Install by Store or Website

Hello, the website for my business will sell <1000 products in UK, EU and US regions, not all regions will have same products but some will. What I want to avoid is being at the mercy of currency fluctuations so I will have separate EURO, GBP and DOLLAR bank accounts per region. I will use sagepay and either paypal or stripe for payment.

My Question is; Do I need to setup my site with 3 separate "websites" even though there is one brand. Each website to have a separate base currency and each using separate merchant ID so that there is no currency conversion needed per region from viewing/selecting/adding product to cart to payment and forwarding of funds to relevant bank account. Is there an easier way of doing this at "Store" level rather than "Website" level.

Thanks

3 stores will be a nice choice for management but a nightmare for server usage and maintenance. Let 's say you have 3 sites like this

yourstore.com => en
eu.yourstore.com => eu
uk.yourstore.com => uk

In any situation you can move uk site to uk server location for the best performance. Other than that, it 's easier to manage all of settings. The same things for other location. I know the management will take more time but you know you can hire each people manage a location in future.

If you use one website for 3 stores then you will meet a lot of problems soon. Other than that, the technique is possible to do for 3 stores.

Thanks bradcode, does that mean it's best to use 3 "websites" under one magento installation rather than 3 "Stores" under 1 "Website" under one magento installation. In the meantime, I have discovered If I edit app/code/core/Mage/Directory/etc/system.xml I can now set base currency at "Store" Level.