My favourites change order a lot depending on my mood, but I'll try to narrow them down as of how I feel about them right now (note: I mostly just play Hu-Card games, so there will be more of those featured, also, I hope you don't mind the western TurboGrafx names)
Hu-Card:
1 - Magical Chase
2 - Soldier Blade
3 - Street Fighter II' CE
4 - Dragon's Curse
5 - New Adventure Island
6 - Jackie Chan's Action Kung Fu
7 - Ninja Spirit
8 - Final Soldier
9 - Super Star Soldier
10 - Detana!! TwinBee
11 - Bomberman '94
12 - Air Zonk
13 - Blazing Lazers
14 - Devil's Crush
15 - Bloody Wolf
16 - Legendary Axe II
17 - Bonk's Adventure
18 - Bonk's Revenge
19 - Valkyrie no Densetsu
20 - Cratermaze
21 - After Burner II
22 - Parasol Stars
23 - Outrun
24 - Coryoon
25 - SideArms - Hyper Dyne
CD:
1 - Asuka 120% Maxima Burning Fest
2 - Akumajou Dracula X Rondo of Blood
3 - Star Parodier
4 - Cotton Fantastic Night Dreams
5 - World Heroes 2
6 - Gate of Thunder
7 - Lords of Thunder
8 - Popful Mail
9 - Ys III Wanderers from Ys
10 - Gradius 2
11 - Ginga Fukei Densetsu Sapphire
12 - Monster Lair
13 - Ryuuko no Ken
14 - Ys IV The dawn of Ys
15 - Ys books I & II
16 - Super Darius 2
17 - Kaze Kiri Ninja Action
18 - Strider Hiryu
19 - Advanced V.G. 2
20 - The Dynastic Hero
21 - Double Dragon 2
There are a lot more games that I like, some that I might even like better than what I've put in the list, but either haven't played them enough, haven't played them in a while or don't feel confident enough about ranking them, besides, it's really tough to choose what are the best games on a system with so many great games in it...
I've considered having ties in some of these rankings, but when my list turned out to have way too many games tied in the top few spots, I've decided against it in the end...