The value of a good prompt.

A prompt holds everything a player is interested in. The tokens for a prompt are as follows (copied from help token)

%h - current hitpoints %m - current mana (0 for vamp)
%H - maximum hitpoints %M - maximum mana (0 for vamp)
%b - current blood (0 for non-vamp) %v - current movement
%B - maximum blood (0 for non-vamp) %V - maximum movement
%g - gold held %x - current experience
%a - your alignment %X - experience needed to next level
%A - invisible/hide/sneak/fade state %S - your current combat style
%T - time of day (RoD time) %u - total number of users
%f - flying affect %U - maximum users online
%o - object currently on auction %w - current weight
%L - command/attack waitstate %W - maximum weight
%n - name of opponent* %G - current geo location
%c - current health of an opponent* %l - new/blank line
%e - numerical timer to show duration of adrenaline**
%s - Shows status of autosac
%i - Shows if you are invisible

The important ones...

%h - current hitpoints %m - current mana (0 for vamp)
%H - maximum hitpoints %M - maximum mana (0 for vamp)
%b - current blood (0 for non-vamp) %v - current movement
%i - Shows if you are invisible %s - Shows status of autosac
%g - gold held %f - flying affect
%a - your alignment %X - experience needed to next level
%A - invisible/hide/sneak/fade state %S - your current combat style
%T - time of day (RoD time) %w - current weight
%L - command/attack waitstate %G - current geo location
%c - current health of an opponent*

Yes. that results in a long prompt. But the results it gives you far outweigh the costs. Hp, mana, blood are self explanatory. (Note how I only keep current blood and movement. max values for both dont really matter. you just need to know you arent out.) The others are slightly less so...
Remember you have TWO prompts. one for while you fight, the other for when you arent fighting.

Alignment: especially at avatar with neutral chars.. you need to be able to tell if there is going to be a possibility you zap after you kill a mob. you dont want to zap of course. knowing this lets you flee or ungroup to prevent that happening.

Flying/invis/hide/sneak indicators: flying should be obvious... mobs trip you, no fly dts will take everything. invis and hide prevent you from being attacked by some aggros. Keep them on at all times if possible

Combat style: You should know where you are. When running, most mobs attack the person in the highest style (to deal the most damage). also above aggressive you cannot flee.. obviously useful to know

Gold held, autosac: thief mobs. lets you know they are there even if you cant see them. also shows up in logs easier if you know where mobs are likely to be. Autosac should be pretty obvious... you dont want to fight to waste all your effort. rule of thumb.. turn autosac off. everyone hates it. The only little use is when you are favoring and need to sac hundreds of corpses. Naturally if you always have autosac off, you dont need the prompt token.

Waitstate: aka lag. each command has different number of bars. 2 bars represent one melee round. if a command is only 1 bar of lag, it means you can perform it twice a round. it also means you can quaff or whatever before the next round starts. obviously good to know when you get bashed or lag proged. spamming commands is the surest way to die in a run. having this in your prompt will prevent it happening as easily as you can watch the bars go down.

Weight: gives you a rough estimate of how many potions you quaffed. Make a mental note before the fight starts, then watch it during the fight. you dont want to run out of potions and not notice till you are dead.

Geo: easy way to tell you moved out of an area and geo. most useful for finding places and mobs to portal/helical/astral to.

Anyhow, these are the prompts I personally use.
prompt
Name:&w(&Y%h/%HHp &C%m/%Mm &G%vMv&w) &Y|&B%a&Y| %T &Y(%G) &R%f%A &g%wkg &p\%L/ %l
fprompt
Name:&w(&Y%h/%HHp &C%m/%Mm &G%vMv&w) &Y|&G%s&Y| %T &amp;R%f &p<&Y%n %c&p> &g%wkg &W%S &p\%L/ %l