April 1999, what was happening? According to Wikipedia, it was some very dark times and not much fun to be had:

Two Libyans suspected of bringing down Pan Am flight 103 in 1988 are handed over to Scottish authorities for eventual trial in the Netherlands. The United Nations suspends sanctions against Libya

In Laramie, Wyoming, Russell Henderson pleads guilty to kidnapping and felony murder in order to avoid a possible death penalty conviction for the apparent hate crime killing of Matthew Shepard
 
 
Bomb explodes in the Valley of the Fallen church in Spain - GRAPO claims responsibility

The first DIY SOS episode is aired on BBC One.
 
 
Ibrahim Baré Maînassara, president of Niger, is assassinated
 
 
A nail bomb explodes in the middle of a busy market in Brixton, South London

Depressing times it seems?  You wouldn't think it though looking at the UK Top 40. Cheese was easily the flavour of the month!

 1 Mr Oizo Flat Beat
 2 The Cartoons Witch Doctor
 3 Britney Spears Baby One More Time
 4 Billie Honey To The Bee
 5 The New Radicals You Get What You Give
 6 Eminem My Name Is
 7 Boyzone When The Going Gets Tough
 8 The Vengaboys We Like To Party! (The Vengabus)
 9 TLC No Scrubs
 10 Phats & Small Turn Around
 11 B*Witched Blame It On The Weatherman
 12 Steps, Tina Cousins, Cleopatra, B*Witched & Billie Thank Abba For The Music
 13 Steps Better Best Forgotten
 14 Des'ree You Gotta Be
 15 Whitney Houston It's Not Right But It's Okay
 16 Robbie Williams Strong
 17 System F Out Of The Blue
 18 Catatonia Dead From The Waist Down
 19 Kele Le Roc My Love
 20 Sash! Colour The World
 21 Cher Strong Enough
 22 Andy Williams Music To Watch Girls By
 23 Blur Tender
 24 The Aphex Twin Windowlicker
 25 The Corrs Runaway
 26 2Pac Changes
 27 Another Level featuring Jay-Z Be Alone No More
 28 George Michael & Mary J Blige As
 29 Steps Heartbeat / Tragedy
 30 Manic Street Preachers You Stole The Sun From My Heart
 31 Tina Cousins Killin' Time
 32 Shawn Mullins Lullaby
 33 Reef I've Got Something To Say
 34 Mariah Carey I Still Believe
 35 Roxette Wish I Could Fly
 36 Blondie Maria
 37 Underworld Push Upstairs
 38 Lenny Kravitz Fly Away
 39 The Beautiful South How Long's A Tear Take To Dry?
 40 Beverley Knight Made It Back '99

Having said that, there really is nothing wrong witha bit of Cheddar! Ok some of it was very stinky [The Cartoons] and some of it was like Marmite [Mr Oizo], but there was also that of the tastier variety [B*witched, Cher. Etc].

One thing that does jump out though is the huge popularity if pop music, Britney was selling songs by the bucketload and Steps had THREE entries in the chart.

The power of advertising was in full swing at the time too, with Des'ree and Andy Williams enjoying chart re-entries.

When it comes to absolute classics though, three songs in the top ten have "timeless" written all over them...