Firstly, I'm a completely neophyte and completely get that Johnnie Walker Blue is probably over rated, and that true scotch connoisseur know better- that's why I'm asking here
I really don't drink often at all, the last time I had a sip of alcohol was months ago. But Johnnie Walker Blue had a smooth drinkability that I love - it's warm and delicious. I think I may buy a 200ml bottle for fun (I know that's tiny, but I don't want to buy a $180 bottle!).. Is there anything else I should try?
I'm glad you posted this thread. I really love Scotch, and I think several people have already shared some useful information for you. I'm going to give you some more, mixed with my own opinion:
Generally speaking, you look to the age for smoothness and the brand/location for distinctive quality. If most Scotch tastes the same for you, and you really are looking for the smoothest you can find, you should be focusing more on the age than the brand. As you correctly guessed, Johnnie Walker is the most overrated of Scotch whiskey - it is not bad, but it is the most well known and one of the most expensive blends.
To get straight to the point, you are looking for something smooth. I would try to get an 18 year (Most people can't tell a significant difference between 18 and 21 for most brands, and the price difference is considerable.) I think you'll enjoy an 18 year Chivas Regal as much or even more than the 21 year JW blue. And you can get 18 year Chivas in the $55-60 range. Not bad for 1/3 the price.
The next step is to look at single malts. Most people don't prefer the Islay malts right off (someone above suggested Lagavulin and Laphroag - two of my favorites. But you probably have to work up to the taste of those. People usually find them too "peaty" - smoky - to their taste.)
Try Glenlivet or Glenfiddich to start your journey into single malts. They are very good values - in many stores their 12 years are the same price as JW black label (12 yr). Since you're looking for smooth, you might try the 18 or 15 year Glenlivet or Glenfiddich. I've seen the 15 year for as little as $40, and usually about $65 for the 18 year.
Some of the suggestions in this thread are excellent, like the 12 year Macallan or the Talisker. But those are usually appreciated only once you start experimenting more and tasting the distinct differences in the single malts. Personally, I love Aberlour (12yr) as a very nice Scotch that most of my friends like, and I can get it under $40. There are many nice Scotches in the $40-50 range, generally 12 year, that you will start to appreciate.
Summary: My advice to start out is to try an 18 yr Glenlivet, or Glenfiddich. Either of those will be under $70 and a MUCH better value than JW blue for a better Scotch.