Man - what a lot of choices there are.

What size do you want to go for (AKA - what sort of budget)?

something like the CMPro Swallow, the Leo or the World Models Groovy if you are prepared to go to a "60-90" size.
If you want to stay with "46 size" maybe the Blackhorse Super air is a good entry level in that size.

Then of course, there are a lot of great bargains in the second hand market too - check the RCU classifieds.

Beware - there are a lot of great choices out there and once you have flown that style of plane, you will be addicted to the (generally) great flying qualities of that style. Try to afford the best servos but there is no need to go overboard (For example - Ht 5955's would be a total waste on any of the planes mentioned above).

Your Decathlon should be able to get you started I have seen them used in the sportsman classes. Try to just get started and no doubt you wil lsee something you like at an event.

I am sure that there will be many other suggestions from others.