My dad shares my same love of series mystery, and we're both big fans of Robert B. Parker, Rex Stout, John Sandford, Sue Grafton, and others. He's been telling me about this series for AGES - how much he loved it, how funny it was, how much he liked the main character...the only thing he couldn't tell me was the name of the author, the titles of the series, or the name of the main character. He just knew he'd read these great books once upon a time.
Finally, over Labor Day weekend, he finally remembered "McNally". After that, it was pretty easy to track down, thanks to the internet.
The series turned out to be the Archy McNally series, by Lawrence Sanders (and later, Vincent Lardo)

McNally's Secret is the first book of the series, and I'll tell you, I was hooked. It's got everything I love: A great main character, fun sidekick, colorful guest characters, good mystery, interesting detective work, and a lot of little details that bring Archy to life.
Archy is a 37 year old bachelor who lives in Palm Beach, Florida. His family is reasonably wealthy, and he occupies a suite of rooms on the third floor of his parents house. He also works for his father. The elder McNally is a lawyer with a stable of insanely wealthy clients who often make unusual demands of him. Archy is the head (and sole employee) of the Department for Discreet Inquiries. He handles all those unusual requests, and generally solves problems. He also generally trips across a body or two in the process.
I'm on the third one now, and I'm still enjoying the series (I've been inspired to try several new cocktails) - but I will say, it's taught me a lesson in not belaboring those little details. I'm about done hearing that Archy's father has his telephone books bound in leather. It's in every book. It's possible that my patience for some of this will run out before the books do, but I doubt it - I'm pretty forgiving if the mystery is good.
Over all - from what I've read so far, I'd recommend this series to anyone who likes fun, slightly fluffy, but genuine mysteries.
McNally's Secret. Putnam's, 1992
McNally's Luck. Putnam's Sons, 1992
McNally's Risk. Putnam's Sons, 1993
McNally's Caper. Putnam's Sons, 1994
McNally's Trial. Putnam's Sons, 1995
McNally's Puzzle. Putnam's Sons, 1996
McNally's Gamble. Putnam's Sons, 1997
*McNally's Dilemma. Putnam's Sons, 1999
McNally's Folly. Putnam's Sons, 2000
McNally's Chance. Putnam's Sons, 2001
McNally's Alibi. Putnam's Sons, 2002
McNally's Dare. Putnam's Sone, 2003.
McNally's Bluff. Putnam's Sone, 2004.
*After the death of Lawrence Sanders in 1998, Vincent Lardo was chosen by the Sanders estate to continue the McNally series.