On your budget, you might consider, for $1299, the 13" MacBook Pro (NON-Retina) with two upgrades: 8GB RAM and 500GB hard drive. If you will be using a professional video editor, you'll want more then 4GB RAM, and the 500GB hard drive is because the base amount might be too little for those huge HD video files and all of the temporary/preview/cache files that are normally created during video editing. You might save a little money if you buy it with 4GB RAM and install the rest from a cheaper supplier like macsales.com.
The MacBook Air would be a contender if you had the budget for it. But if you were to stay under $1299 you would be stuck with the 1.3GHz i5 processor, 4GB RAM, and a 128GB SSD that is very small for video editing. While the SSD helps make up for a slow processor and inadequate RAM, the SSD for the $1299 model is simply too small to take on all those extra swap files and have the space for video editing too. An external hard drive (for working files, not as a backup) would be mandatory, which would push you over your budget, but even then the system drive might still be too small when all of the ancillary files generated during production are taken into account.
The 5400 vs 7200 RPM debate is no longer relevant today because a 7200RPM drive is no longer an option for the MacBook Pro. Anyone who is serious about performance today would completely skip over the 7200RPM drives and go straight to SSD. Unfortunately, your budget of $1300 is too low to include an SSD of a size that would be appropriate for serious video editing.