Im playing with slightly reduced </iTechCostModifier> and these settings in CIV4GameSpeedInfo.xml.
Give it a try if your curious, its a bit different than default but I like it. It forces decisions in terms of what buildings to build and these decisions aren't just about what order to build them in
- plus I find this tech speed much more satisfying, I'd probably play a faster speed such as a modified marathon if I wanted to turn tech trading off, just personal preference I guess.
<Type>GAMESPEED_SNAIL</Type>
<Description>TXT_KEY_GAMESPEED_SNAIL2</Description>
<Help>TXT_KEY_GAMESPEED_SNAIL_HELP</Help>
<iGrowthPercent>750</iGrowthPercent>
<iTrainPercent>450</iTrainPercent>
<iConstructPercent>700</iConstructPercent>
<iCreatePercent>1000</iCreatePercent>
<iResearchPercent>1000</iResearchPercent>
<iBuildPercent>600</iBuildPercent>
<iImprovementPercent>625</iImprovementPercent>
<iGreatPeoplePercent>625</iGreatPeoplePercent>
<iCulturePercent>625</iCulturePercent>
Give it a try if your curious, its a bit different than default but I like it. It forces decisions in terms of what buildings to build and these decisions aren't just about what order to build them in

<Type>GAMESPEED_SNAIL</Type>
<Description>TXT_KEY_GAMESPEED_SNAIL2</Description>
<Help>TXT_KEY_GAMESPEED_SNAIL_HELP</Help>
<iGrowthPercent>750</iGrowthPercent>
<iTrainPercent>450</iTrainPercent>
<iConstructPercent>700</iConstructPercent>
<iCreatePercent>1000</iCreatePercent>
<iResearchPercent>1000</iResearchPercent>
<iBuildPercent>600</iBuildPercent>
<iImprovementPercent>625</iImprovementPercent>
<iGreatPeoplePercent>625</iGreatPeoplePercent>
<iCulturePercent>625</iCulturePercent>