I do believe that we have to analyze things once in a while, so I got here from Twitch the Top 15 Korean Series in 2006: Peak and average ratings. 
Peak / Highest rating the series achieved
- 44.5% Dear Heaven SBS
- 40.1% Jumong - Prince of the Legend MBC
- 37.9% The Bizarre Bunch KBS
- 35.9% 7 Princesses KBS
- 31.9% Goodbye To Sadness KBS
- 28.6% Pure 19 KBS
- 28.3% Princess Hours MBC
- 26.7% The Ballad of Seo Dong SBS
- 24.9% My Girl SBS
- 24.7% Yeon Gaesomun SBS
- 24.5% Love & Ambition SBS
- 23.7% That Woman SBS
- 23.0% Golden Apple KBS
- 22.4% Soon-Ae, Please Come Back SBS
- 22.3% Thank You, Life KBS
Average Rating check the number of episodes
- 31.55% Jumong MBC - This is still aired in the Philippines and it also has a good ratings here too. spoiler (81 episodes - historical drama)
- 31.13% The Bizarre Bunch KBS1 [C] - 170 episodes
- 26.18% Dear Heaven SBS [C]
- 25.46% 7 Princesses KBS2
- 25.26% Goodbye To Sadness KBS2 [C] - 60 episodes
- 24.07% Pure 19 KBS1 - 167 episodes
- 22.20% Princess Hours MBC [C] - 24 episodes
- 21.20% Yeon Gaesomun SBS - 100 episodes - historical drama
- 20.94% My Girl SBS [C] - 16 episodes
- 19.48% Soon-Ae, Please Come Back SBS - 16 episodes
- 19.42% The Ballad of Seo Dong SBS [C] - 55 episodes - historical drama
- 17.80% Thank You, Life KBS2 [C] - This is different from Thank You which was aired 2007
- 17.43% Golden Apple KBS2 [C] - 30 episodes
- 17.24% Love & Ambition SBS
- 16.26% To Marry a Millionaire SBS [C] - 16 episodes
Though statistics gives us idea of what series Koreans love to watch last year, we still can’t rely on this 2006 summary of ratings. We still must consider other details like competing program, Korean stars, type of audience it appeals to, and the period the TV series was aired. Why did I say this? Because I haven’t seen Which Star are you From?, Love Truly, and Vineyard Man on the Average Ratings Summary. 
even on the peak ratings. Oh, well. 
To see the complete list of Peak and Summary ratings from Twitch click here. Don’t forget browsing up to to the bottom page of this link because you might find interesting infos from the dramas you already watched or planning to watch like links to official websites, photo galleries, and wallpapers.
Another useful Twitch page for dramas completed in half 2006
These are the ratings of 2006 Korean dramas I already watched:
My Girl (Drama Special)
16 Episodes - Aired from 12/14/05 to 2/2/06 [SBS]
Cast: Lee Da-Hae, Lee Dong-Wook, Lee Joon-Gi, Park Shi-Yeon, Byun Hee-Bong, Ahn Seok-Hwan, Choi Ran, Lee Sa-Bi, Hwang Bo-Ra
RATINGS: AVERAGE 20.94%, PEAK 24.9%, LOWEST 14.6%Note: It was aired here everyday at 9.30 PM before A love to Kill at 10PM. Watching this drama makes me giggle and happy the next day. But love to Kill makes me giggle and sad. So I had mixed emotions when I woke up.
Princess Hours/ Goong / The Palace (Wed/Thu Drama)
24 Episodes SEASON 1 - Aired from 1/11 to 3/30/06 [MBC]
Cast: Yoon Eun-Hye, Joo Ji-Hoon, Kim Jung-Hoon, Song Ji-Hyo, Kim Hye-Ja, Shim Hye-Jin, Im Ye-Jin, Gang Nam-Gil, Kim Seok, Kim Sang-Joong, Song Seung-Hwan, Lee Ho-Jae, Lee Yoon-Ji
RATINGS: AVERAGE 22.20%, PEAK 28.3%, LOWEST 13.7%
Over The Rainbow (Wed/Thu Miniseries)
2006/07/26~ [Airs Every Wed/Thu Nights on MBC]
Cast: Fanny (Fly To The Sky), Seo Ji-Hye, Kim Ok-Bin, Ji Hyun-Woo, Im Ha-Ryong, Kim Hye-Ok, Kim Il-Woo, Na Hye-Mi, Shin Hyun-Tak, Choi Kwon, Na Woo, Poppin’ Hyun-Joon, Lee Hyung-Cheol, Jung Han-Yong
RATINGS: AVERAGE 8.40%, PEAK 8.4%, LOWEST 8.4%Note: This drama is about following your passion. It appeals to teenagers most probably, or to viewers who love to dance.
The Vineyard Man (Mon/Tue Drama)
2006/07/24~ [Airs Every Mon/Tue Nights on KBS2]
Cast: Yoon Eun-Hye, Oh Man-Seok, Ok Ji-Young, Kim Ji-Seok, Kang Eun-Bi, Lee Soon-Jae, Yoon Moon-Shik, Seonwoo Yong-Nyeo
RATINGS: AVERAGE 7.85%, PEAK 7.9%, LOWEST 7.8%Note: Gosh, poor ratings.
But this series is great because it talks how pure love is developed through time. Love the ending.
Currently Watching
Which Star Are You From (Mon/Tue Drama)
16 Episodes - Aired from 03/13 to 05/02/06 on MBC
Cast: Kim Rae-Won, Jung Ryeo-Won, Kang Jung-Hwa, Park Shi-Hoo, Im Ye-Jin, Ok Ji-Young, Kim Ha-Gyun, Song Jae-Ho
RATINGS: AVERAGE 15.23%, PEAK 17.9%, LOWEST 10.8%Note: Kim Rae Won is here.:smile: I’m currently watching the series!!! I’m halfway and I like it.
Love Truly / I Really Really Like You (HD Weekend Drama)
2006/04/08~ [Airs Every Sat/Sun Night on MBC]
Cast: Eugene, Lee Min-Gi, Ryu Jin, Geum Bo-Ra, Jang Yong, Choi Buram, Kim Hye-Ok, Jung So-Young, Yoon Yeo-Jung, Lee Young-Ja, Kim Chang-Wan, Kim Guk-Jin
RATINGS: AVERAGE 12.94%, PEAK 17.1%, LOWEST 9.6%Note: I love Lee Min Ki. Is he the other guy here? Anyway the soundtracks are great. Collectible!!