Yes, general consensus seems to be that an "i" or "e" prefix does not significantly affect value. I differ somewhat from this view and count an i/e as an additional word. However, in general, if it's valuable without an i or e, then it's valuable with one.
Here's some recent "i" sales to give you an idea:
Domain TLD SalePrice SaleDate SaleThru
iGame com $26,050 Jun 05 SnapNames
iTrain com $20,300 Nov 05 Moniker/Domain Systems
iBegin com $14,501 Oct 05 Private Sale
iStudio com $13,603 Aug 05 Sedo
iPal com $10,450 Oct 05 SnapNames
iMesh de $6,910 Sep 05 Sedo
iFlorist co.uk $4,718 May 06 Sedo
iCompany com $4,600 Dec 05 SnapNames
IFlorist co.uk $4,566 May 06 Sedo
iCache com $3,888 Jul 05 Afternic
You can find more by entering "i" or "e" as the keyword (see site in sig).
Cheers,
BidNo