Respectfully disagreeing with you. HIIT is a great idea. Everyone should do cardio (within their limits...) Strength training (with or without weights) and cardio, either on opposing days, or spread AM/PM work outs is the best way to go.
April, if you're already in good physical condition, check out an HIIT (High intensity interval workout) program like Insanity or P90X (I've found that a lot of women I know prefer the P90X to insanity.) I'm going to be starting my second Insanity cycle of the year, and am hoping to get a couple local crazies to work out with.