Hi guys, I loved games but currently don't have enough times to play complicated games these days. That's why I prefer DS lite. They have tons of small, simple, time waster type of games, perfect for waiting on appointment (doctor, meetings, clients, boarding, etc), or during flight. The DS keeps me sane for waiting and never leaves my bag/pocket.
My recommendations:

Brain Age 1 & 2
Big Brain Academy
Club House Games (42 games, hearts, blackjack, turncoat, love it but have bugs on 'connect five' which frustrates me)
Cooking Mama
Diner Dash
Electroplankton (not really games, it's a music conducting games, quite unique and fun)
Feel the Magic xx-yy (hillarious small games, highly recommended, one of my must have lists)
Flash focus
Meteos
Metroid prime Pinball (It's pinball)
New Super Mario bros
Osu Tatakae Ouendan (Music games, hillarious, the Americanized ver. is "Elite beat Agents" which not quite as hillarious, more like lost in translation, so pick this one instead of Elite Beat Agents)
Polarium
Picross (puzzle games using logic and deduction, more like minesweeper in windows)
Zoo Keeper (Bejeweled knockoff)
Warioware touched (small games, prefer Feel the magic though)
Top Spin2 (Tennis Games)
Winning eleven (Soccer Games)
Tetris DS
Sudoku Platinum (Best Sudoku games for DS)
Space invader revolution (old school games)

So any DS lovers here? What's your favourite games?