One of the more interesting new zoning laws which becomes effective July 1, 2011 (that's right, next year, not this!) extends the mandatory consistency of the General Plan in those jurisdictions where the Planning Commission has recommended and the local legislative body has adopted the General Plan. This is a distinct minority of Tennessee jurisdictions: most General Plans are adopted by the Planning Commission and no legislative action is needed.
But in those areas where it is, Chapter 648 of the 2010 Tennessee Pubic Acts requires that not only must any land use decision by the legislative body and planning commission be consistent with the plan, but so too must all zoning board decisions (excepting variances). For attorneys as well as applicants to the effected zoning boards, this may add another wrinkle in the application process. The applicant will have to prove consistency with the plan, or possibly face reversal on appeal.
Let me say that it may be necessary under the state laws in effect now (in fact I usually try to prove such consistency whenever I am in front of a zoning board) so that perhaps this isn't such a big deal. However, Chapter 648 makes the requirement much more pointed, and opposing parties may find this fairly easily and thus have another argument to invalidate a zoning board decision.
I would be remiss if I did not mention that the 2008 amendment that authorized adoption of general plans by the local legislative body permits but does not require the planning commission to request adoption of the plan by the legislative body. In effect, once such a request is made and the plan adopted by the LLB, the plan becomes a creature of the LLB, and not of the planning commission. The City of Columbia Planning Commission has made such a request; I don't recall hearing if the plan was ultimately adopted by the local legislative body or not. There may be other examples but as of yet, I believe they are few and far between.
Take a look at Tenn. Code Ann. § 13-4-202(b) to understand the basic premise behind the statutory scheme; Tenn. Code Ann. § 13-3-304(b) is the companion regional provision.