The 188 is an excellent choice and easily the most popular combo unit in that price range, great chartplotter that uses the Garmin Blue Chip cartography (IMHO, better then either C-Map or Navionics) along with a 500 watt (rms), dual frequency fishfinder built-in, sweet unit. The only other combo unit in this price range I would consider is the Furuno 1650, very similar features and now that the price is in the same ball park as the Garmin the only thing that keeps me from picking this over the Garmin is the fact that it uses the other cartography (your choice, it will take either C-map or Nav.) You really can't go wrong with either of these units/brands.
I wouldn't be suprised if the Lowrance and or Raymarine fans voice their opinions on their units but let me just say from working in the industry, there are far more dissappointed/unhappy Lowrance and Ray customers then there are Garmin or Furuno.