I remember when the only available web browser was the "Mozilla suite", which was extremely slow and basically unusable.In this period, Netscape 4.x still worked pretty well and was available on Linux. Opera was also available for Linux at that time. So, it's definitely not true that the Mozilla Suite (which was indeed horrible) was the only available browser.
You could not play MP3 files out of the box due to patent issues.
I remember mpg123, xmms, etc. being available in many distributions. It was primarily Red Hat who didn't distribute MP3 support out of the box. IIRC free decoders were exempt from the decoder licensing fees.
Most graphic cards only worked in VESA mode, so we had no 3D acceleration of any kind.
Around 2000 there were not that many 3D chipsets. 3DFX was still ruling the world and there was 3D support for Linux per Glide. Many 2D accelerators did have support (e.g. Tseng Labs ET series, Matrox chipsets, ATI chipsets, most S3 chipsets). I had a 3DFX Voodoo 3 and was playing accelerated OpenGL games on Linux. I remember tinkering with NetBSD and having to go back to software rendering, which was frustrating.
But the worst thing was the lack of fonts. Fonts were truly abysmal.
Erm, Microsoft's 'Core fonts for the Web' were distributed since 1996. There has been a Sourceforge project (msttcorefont) distributing the fonts since Microsoft took them offline. Many distributions had an installer or package to get these Microsoft fonts. Then you had all the usual Windows fonts.