Depends wheter you want to retain your old chips. Hopefully not, as the chips for your old plotter are raster scans and therefore not "the best"
Definitely get colour imho. Much easier to read, you get the info you need with less time looking down at the dash.
Handheld is a good idea. In which case, garmin 176c is the best handheld, no contest. This runs on bluecharts
If you want built in, then the colour Navman is inside your price limit. If you could stretch the budget, the cheapest of the "serious" brands (Garmin, Simrad, furuno, Ray) is Simrad CP33 which is a great bit of kit. About £1200 I think
Most of these take CMap NT chips. I can sell you a solent Cmap NT, 18 months old, for 50% of new price.