We are looking at using Cassandra to store a stream of information coming from various sources.
One issue we are facing is the best way to query between two dates.
Cassandra rows can be very large, so consider modeling it as columns in a row rather than rows in a CF; then you can use the column slice operations, which are faster than row slices. If there are no "natural" keys associated with this then you can use daily or hourly keys like "2010/02/08 13:00".
Otherwise, yes, using range queries (get_key_range is deprecated in 0.5; use get_range_slice) is your best option.