A D7 port of the CCK Money field is being worked on: http://drupal.org/node/908480
One handy adjunct to the CCK Money field is the currency conversion jQuery widget which allows your visitors to convert the value to any currency, calculated on the fly via Yahoo finance, though you could implement something like that on your own using any of several existing jQuery scripts out there. Not sure if the D7 port includes the conversion widget. You can see an example of the widget on my real estate site here (look for the sales price and click the little icon): http://www.bigmangoproperties.com/thailand/pattaya/condominium/ad-hyatt/26041
If you just want a selection of a few currencies as a suffix label only, you can use the Double Field module, or for a single currency label just use a Decimal field type and use the suffix for the currency label.
For calculations you can use the Computed Field module, though using Commerce with Rules is arguably more powerful.