What sort of subjects? A ring flash is generally best suited to documentary images (medical/dental, stamp collection, etc.), because they produce a 'flat' light. Even the better ones like the Canon MR-14EX, which have two tubes that can be set to different power, don't give much dimensionality. If you're shooting creatively, I'd consider other options.
A better solution to consider is a regular Speedlite with a long flash bracket (I like the Manfrotto 233B for this), an off-camera cord, and a small softbox (Lumiquest, etc., ~8x8") positioned over the front of the lens.
Another excellent option (budget permitting) is the MT-24EX Twin Lite. Ideally, rather than the little ring at the front of the lens, mount the heads on a separate brackets for complete flexibility in positioning. I use a pair of Wimberley F-2 macro brackets for that.
Hope that helps...