Throwing the cat into the bag here (sorry Phanx, I love cats!) ... I found that if I wanted to use the auction house, I had to disable a huge swatch of AddOns, or at least the ones not related to inventory or auctions. I do plan on doing the half by half by half thing until I find the culprit.
What's this have to do with debugging? I first noticed it when BugSack threw an error that it oddly couldn't keep because of WoW's fatal error.
Code:
!BlizzBugsSuck
!BugGrabber
_NPCScan
_NPCScan.Overlay
+Wowhead_Looter
Ace3
AceGUI-3.0-SharedMediaWidgets
AckisRecipeList
AckisRecipeList_Alchemy
AckisRecipeList_Blacksmithing
AckisRecipeList_Cooking
AckisRecipeList_Enchanting
AckisRecipeList_Engineering
AckisRecipeList_FirstAid
AckisRecipeList_Inscription
AckisRecipeList_Jewelcrafting
AckisRecipeList_Leatherworking
AckisRecipeList_Smelting
AckisRecipeList_Tailoring
ACP
AddonLoader
AddOnSkins
AdiBags
AdiBags_Config
Altoholic
Altoholic_Achievements
Altoholic_Agenda
Altoholic_Characters
Altoholic_Grids
Altoholic_Guild
Altoholic_Search
Altoholic_Summary
Archy
Arh
AskMrRobot
Astrolabe
AtlasLoot
AtlasLoot_BurningCrusade
AtlasLoot_Cataclysm
AtlasLoot_Classic
AtlasLoot_Collections
AtlasLoot_Crafting
AtlasLoot_Factions
AtlasLoot_MistsofPandaria
AtlasLoot_Options
AtlasLoot_PvP
AtlasLoot_WarlordsofDraenor
AtlasLoot_WorldEvents
AtlasLoot_WrathoftheLichKing
Auc-Advanced
Auc-Filter-Basic
Auc-ScanData
Auc-Stat-Histogram
Auc-Stat-iLevel
Auc-Stat-Purchased
Auc-Stat-Simple
Auc-Stat-StdDev
Auc-Util-FixAH
BarovHelper
BeanCounter
BigWigs
BigWigs_Achievements
BigWigs_BlackrockFoundry
BigWigs_BurningCrusade
BigWigs_Cataclysm
BigWigs_Classic
BigWigs_CommonAuras
BigWigs_Core
BigWigs_Draenor
BigWigs_EndlessSpring
BigWigs_HeartOfFear
BigWigs_Highmaul
BigWigs_Mogushan
BigWigs_NezirIcePatch
BigWigs_Options
BigWigs_Pandaria
BigWigs_Plugins
BigWigs_Ra-denAssist
BigWigs_SiegeOfOrgrimmar
BigWigs_ThroneOfThunder
BigWigs_Voice
BigWigs_WrathOfTheLichKing
BigWigs_YorsahjPriority
bigwigs_zonozzicons
Blizzard_AchievementUI
Blizzard_ArchaeologyUI
Blizzard_ArenaUI
Blizzard_AuctionUI
Blizzard_AuthChallengeUI
Blizzard_BarbershopUI
Blizzard_BattlefieldMinimap
Blizzard_BindingUI
Blizzard_BlackMarketUI
Blizzard_Calendar
Blizzard_ChallengesUI
Blizzard_ClientSavedVariables
Blizzard_CombatLog
Blizzard_CombatText
Blizzard_CompactRaidFrames
Blizzard_CUFProfiles
Blizzard_DebugTools
Blizzard_EncounterJournal
Blizzard_GarrisonUI
Blizzard_GlyphUI
Blizzard_GMChatUI
Blizzard_GMSurveyUI
Blizzard_GuildBankUI
Blizzard_GuildControlUI
Blizzard_GuildUI
Blizzard_InspectUI
Blizzard_ItemAlterationUI
Blizzard_ItemSocketingUI
Blizzard_ItemUpgradeUI
Blizzard_LookingForGuildUI
Blizzard_MacroUI
Blizzard_MovePad
Blizzard_ObjectiveTracker
Blizzard_PetBattleUI
Blizzard_PetJournal
Blizzard_PVPUI
Blizzard_QuestChoice
Blizzard_RaidUI
Blizzard_ReforgingUI
Blizzard_StoreUI
Blizzard_TalentUI
Blizzard_TimeManager
Blizzard_TokenUI
Blizzard_TradeSkillUI
Blizzard_TrainerUI
Blizzard_Tutorial
Blizzard_VoidStorageUI
BodyguardHealth
Broker_Currency
Broker_HitCrit
BugSack
CallbackHandler-1.0
ChocolateBar
ChocolateBar_Options
ClassTimer
Clique
Collectinator
CoolLevelUp
CoolLine
Cromulent
DataStore
DataStore_Achievements
DataStore_Agenda
DataStore_Auctions
DataStore_Characters
DataStore_Containers
DataStore_Crafts
DataStore_Currencies
DataStore_Garrisons
DataStore_Inventory
DataStore_Mails
DataStore_Pets
DataStore_Quests
DataStore_Reputations
DataStore_Spells
DataStore_Stats
DataStore_Talents
Diplomancer
ElkFactions
ElvUI
ElvUI_ChatTweaks
ElvUI_ChatTweaks_Debug
ElvUI_ChatTweaks_Extra
ElvUI_ChatTweaks_Spam
ElvUI_Config
ElvUI_CustomXP
ElvUI_Enhanced
ElvUI_EverySecondCounts
Enchantrix
Enchantrix-Barker
EventHorizon
EventHorizon_Deathknight
EventHorizon_Druid
EventHorizon_Hunter
EventHorizon_Mage
EventHorizon_Monk
EventHorizon_Paladin
EventHorizon_Priest
EventHorizon_Rogue
EventHorizon_Shaman
EventHorizon_Warlock
EventHorizon_Warrior
FeedTillers
FlightMap
FlightMapEnhanced
FollowerGearOptimizer
GarrisonMissionManager
GatherMate2
GatherMate2_Data
Grail
Grail-Achievements
Grail-Reputations
Grail-When
GTFO
GuildBankSearch
HalionHelper
HaloPro
HandyNotes
HandyNotes_DraenorTreasures
HandyNotes_TreasureHunter
Hydra
Informant
LibAbacus-3.0
LibAboutPanel
LibBabble-Artifacts-3.0
LibBabble-Boss-3.0
LibBabble-DigSites-3.0
LibBabble-Faction-3.0
LibBabble-Inventory-3.0
LibBabble-ItemSet-3.0
LibBabble-Race-3.0
LibBabble-SubZone-3.0
LibBabble-Zone-3.0
LibBars-1.0
LibBodyguard-1.0
LibBossIDs-1.0
LibButtonGlow-1.0
LibCandyBar-3.0
LibChatAnims
LibCompress
LibDBIcon-1.0
LibDDI-1.0
LibDeformat-3.0
LibDialog-1.0
LibDualSpec-1.0
LibGuildBankComm-1.0
LibItemUpgradeInfo-1.0
LibJostle-3.0
LibMapData-1.0
LibPeriodicTable-3.1
LibPetJournal-2.0
LibQTip-1.0
LibSharedMedia-3.0
LibSink-2.0
LibStrataFix
LibStub
LibTextDump-1.0
LibTextTable-1.1
LibToast-1.0
LibTourist-3.0
LibWindow-1.1
LittleWigs
Masque
MasterPlan
Mediapack
Mendeleev
MikScrollingBattleText
MillHelp
MillHelp_Glyphs
MobileVault
MobileVault_Options
MobileVault_Sharing
MSBTOptions
NeedToKnow
OpenRaid
OPie
Overachiever
Overachiever_Tabs
Overachiever_Trade
PetJournalEnhanced
RealIDToons
Routes
SharedMedia_ClassicalFonts
SharedMedia_NoAsianFonts
SharedMediaAdditionalFonts
SharedMediaAdditionalSounds
Sifter
Skada
Skillet
SmartRes2
SorhaQuestLog
Squire3
Squire3_Config
Stubby
Surprise
teksLoot
TimelessMemoryHelper
TimeToDie
TomTom
Touhin
TradeSkillInfo
TradeSkillInfoUI
WeakAuras
WeakAurasModelPaths
WeakAurasOptions
WeakAurasTutorials
Wholly
WoWDBProfiler
WowheadBagScanner
ZygorGuidesViewer