I always enjoy the "low budget" suggestions. $600+
Assuming that you are not a fanboy/collector/lover etc of just one brand or type, try to have fun experiencing as many designs/countries as possible. This forum is US based/biased/oriented, but try to get some lower cost knives from other countries too, in addition to Victorinox.
Even a basic Opinel may provide excitement and variety if you only have the usual US designed knives. You may then want to expand, for example, into knives similar to opinel made by old bear or nontron, if you want to keep to a theme.
Same with Laguiole knives, friction folders (Svord is a good basic starting point) and so on.
Even with US brands, you may try some products they have made in other countries, like in Italy, Japan...
Keep to low cost, decent quality and buy what interests you.