eXPerience

I get where the Microlite experience system is coming from - counting up encounter levels (EL) is simple and easy to work with, but for my mind I need to have wiggle room to add or subtract the amount of experience based on game play and for that I wanted more granular units.  I could have worked with EL if I hadn't wanted to give XP for spent treasure or hand out little XP perks for good game moments.  As it is I went with a general goal of 100XP per HD so that I could throw in 25 or 30 XP here and there.  Going with this makes it easy to put the level requirements at multiples of 1000 so level 1 is 1000XP, level 2 would be 2000, level 11 would be 11000.   I also like handing out 25 and 50 XP bonuses for little game play things like figuring out the magic lever or babysitting the kolbolds.  If I were to be running on a level *100 system I would be worried about handing out too much or seeming miserly handing our 1 or 2 XP.  I did like the mechanic in Microlite of once you level you wipe out your XP and start counting again - for no particular reason except simplified record keeping.

Now when I say a 1HD monster is worth 100 XP that doesn't mean that all 1 HD monsters are worth 100 XP.  A little 3hp goblin is not worth 100 XP, a crazed dwarf with his torch over a pool of oil probably is.  I like to mix it up a little when handing out XP but you could follow the basic system and assign a straight 100/HD and it should work out.  You can even go with a variant with 50/HD or 200/HD depending on how long you want to play out each level and it should work well since level * 1000 is pretty simple to work with. 

I'm not worried that it doesn't average out with or track with experience point tables in d&d or other d20 style game in particular.  I think that the with difference in game styles and difficulties and amounts of treasure in d20 fantasy systems already out there you can get away with this and still track pretty well with the modules and supplements at each level no matter how you got there.  Some games are tough and some are Monty Haul and a  level 4 cleric is probably going to be pretty much the same mechanically whether you got there in one adventure or in six.

As for experience for spending treasure - well I think this is a great idea to get dragged out of the old school systems.  Giving XP for spending treasure does two things - it rewards lots of adventuring things aside from combat and it gets rid of treasure so that players need to get more.  Also having to spend it on 'tithes and training' makes sure it gets spent and not just converted to some other kind of swag.  The 10 to 1 rate of exchange is a guesstimate based on what I consider my treasure levels will be.  I wanted to make the treasure component less than 1/3 of the XP so I pegged it to 10gp.   I can see a good adventurer at level 8 accumulating 25,000gp to spend on training and charity somehow. And if they are not wanting to part with their money, well they'll be out there fighting it up then.