omg, there are so many tomato varieties! I keep trying out new ones and growing a bunch of different ones but have trouble reducing the list!
Everyone here on our island seems to love Sungold, which many others have mentioned and also Juliet, which I think are what you call a "Saladette" type, smallish oblong, bright red. Juliets are great for drying as well as fresh eating or canning (they make your sauce nice and bright). both are prolific, both are hybrids so you can't save your own seeds.
My honey's favourite is Amish Salad for fresh eating.
My friend who's been gardening for decades with a specific focus on flavour prefers Rose de Berne.
I quite like the unique flavours of Persimmon and Green Zebra, and like to grow a colourful mix of cherry tomatoes, this year Gardener's Delight (red) were my favourite, Black Cherry is also good. I tried out some new slicers this year but I think "Andrew Rahart's Jumbo Red" which I got from Heritage Harvest Seeds in Manitoba, Canada is still top of my list flavour wise
Someone else mentioned Stupice, which is a good early, tasty, reliable and prolific variety that's worth trying out. In general, "heirloom" varieties are a good place to start for good flavour. Start requesting seed catalogs now so you have lots of time to narrow down your selections!
We did a tomato taste test at the Fall Fair one year which was really fun. It's neat to see how different the same variety grown in a different garden can taste!