Another implementation to @dieseltravis compare jQuery version strings gist https://gist.github.com/2662417 Demo in comments.

gistfile1.js

var jQueryVer = {
    isEqual: function (test, act) {
        this.version = test || this.version;
        if (this.version) {
            //if actual jquery version is passed in use that if not get it.
            act = act || jQuery.fn.jquery; 
            return this._compare(act); 
        }            
    },
    //Boolean value on if the actual jQuery Version is greater then the test version.
    greater: null,
    //Boolean value on if the actual jQuery Version is lower then the test version.
    lower: null,
    version: null,
    _compare: function(actVer) {
        
        var testVer = this.version,
            _alpha = /[a-z]+(\d+)/gi, 
            getArray = function (v) {
                // replace rc1, rc2, beta3, etc with .-1.1, .-1.2, .-1.3, etc
                return v.replace(_alpha, ".-1.$1").split(".");
              }, 
            a, 
            b, 
            maxLength,  
            parseVer = function (v) {
                var hasLetters = /[a-z]/gi;
                return (v) ? (hasLetters.test(v)) ? -1 : parseInt(v, 10) : 0;
            };
        // quick test of equality before digging in
        if (actVer === testVer) {
            this.greater = this.lower = false;
            return true;           
        }
        
        a = getArray(testVer);
        b = getArray(actVer);
        maxLength = Math.max(a.length, b.length);

          // verify both arrays are the same size
          a.length = maxLength;
          b.length = maxLength;

          for (var i = 0; i < maxLength; i++) {
            var _a = parseVer(a[i]),
                _b = parseVer(b[i]);
            this.greater = !(_a > _b);
            this.lower = !(_a < _b);
            if (this.greater !== this.lower) 
                return false
          }

          // all equal at this point
          return true;   
    }
};

jQueryVer.version = "1.6.4";
console.log(jQueryVer.version); //1.6.4
console.log(jQueryVer.isEqual()); //false
console.log(jQueryVer.greater ? "Version is greater" : jQueryVer.lower ? "Version is lower" : ""); //Version is greater
console.log((jQueryVer.isEqual("1.7.1"))); //true
console.log(jQueryVer.version); //1.7.1
console.log(jQueryVer.isEqual("1.8.2")); //false
console.log(jQueryVer.version); //1.8.2
console.log(jQueryVer.greater ? "Version is greater" : jQueryVer.lower ? "Version is lower" : ""); //Version is lower

Demo http://jsfiddle.net/zr4BU/