Ive been a whittlin' maniac since I joined this forum about 5 years ago and I am so grateful for it.
My favorite tools (mostly carbon steel) are:
1. GEC 62 Easy Pocket Congress (carbon/stag)
2. Mora carver (think that's the name but it has impeccable ergonomics and blade geometry with an easily maintainable convex edge)
3. GEC 47 Viper wharncliffe (carbon/lava acrylic)
4. Case 9 dot 6347 ( SS

) with the most impressive red jigged bone (3 blades = convenient)
5. Spyderco Military (not traditional by any means but it does make a great whittler

)
Locking knives or fixed blades (traditional or otherwise) do allow you to put more torque in directions that could threaten a finger if using a non locking blade, but a lock is definitely not necessary because you're gonna cut yourself a lot anyway

You can make some pretty amazing things with time and patience and you also find a great way to temporarily escape from life. I love it.
Multi blade traditional slipjoints (stockman or congress) in carbon steel with a wharncliffe/sheepsfoot blade option would be my recommendation because it teaches you how to utilize other blade profiles and with a 4 blade congress you can sharpen the redundant blade to a seriously low angle.
Please share your work with us and check out the past threads of some of the amazing things our forum brothers/sisters can create.