Recommended PS1 plugins

Firstly, stop using ePSXe and use PCSX-R.

GPU

• 3D: PEOPS OpenGL 1.78   (Comes with PCSX-R, has an anti-jitter funtion "GTE accuracy", and allows driver forced AA)
• OpenGL 2.9 (If you run into problems with 1.78, want to use filters. Or want to set a custom rendering resolution for within the fullscreen box, aka window resolution.)
• 2D: gpuBladeSoft 1.41   (Very accurate, but renders everything on CPU so can be very demanding at high resolutions. Fairly buggy past native as well, with texture alignment and whatnot.)

 SPU

• P.E.Op.S 1.10 beta
• Eternal SPU 1.5

 Input

• LilyPad latest SVN (under Input APIs set Keyboard API to Raw Input)
• LilyPad-SCP (Comes with the driver, which is a very nice alternative to MalwareinJoy)
• Pokopom Xinput Pad Plugin 2.0
• LilyPad-MotioninJoy (if you've a DS3 and are using MiJ)

Bios

Don't use simulated BIOS, download and use a real BIOS.

No plugins

Also if you don't want to use plugins, and want something that just werks, then use XEBRA, or RetroArch.