This is probably the best radar, with storm track, the ability to zoom in, and a huge variety of other features. For advanced radar types on the Weather Underground site, hover your mouse over the "Advanced Radar Types" image that is located along the left edge of the radar image.
Weather Underground's WunderMap - Interactive Radar
Weather Underground's WunderMap is one of the best weather tools available. It allows you to view radar data combined with weather station and satellite data. You can choose what you want on the map. You can zoom in as close as your house or as far away as you want. They have a large amount of other features available to add to the map.
Weather.com Interactive Radar
This site also has layers such as clouds, temps and winds.
National Weather Service Radar
This is another good site for radar. Unlike the Weather Underground site, you can pause the radar on this one. It uses Java for loops on this site, so you will need it to use the loops. There is also regional views.
This site is good to use to view an entire regions worth of radar data. If you want to see a large part of the storm in one radar as it makes landfall, this is a great radar to do it with. The radar loops on this site are also longer which is a nice feature to use.
Aruba - As of posting this, they link to Venezuela radar. There was previously radar for the region (Aruba, Bonaire and Curacao) on another site before the Netherlands Antilles was dissolved.
Bahamas - Not available as of posting this.
Curacao - As of posting this, they have no radar listed on their site. See Aruba or Venezuela. There was previously radar for the region (Aruba, Bonaire and Curacao) on another site before the Netherlands Antilles was dissolved.
Dominican Republic - Not available as of posting this.
Guantanamo Bay: NOAA Short Range (Sometimes outdated)
Guyana - Not available as of posting this.
Jamaica: 240km - Not available as of posting this. Make sure the time is current if imagery is available.
Martinique: Antilles (Larger View) | Caribbean Radar Mosaic (Larger View)
On the larger view page: "Précédente | Animation | Arrêt | Suivante" -> "Previous | Animation | Stop | Next"
Panama Canal, Panama
Puerto Rico: Weather Underground Long Range | NOAA Long Range
Trinidad and Tobago - The first two ranges have other radar products available too. 150km | 250km | 400km
Venezuela - Some radar sites cover Aruba, Bonaire and Curacao.