EmailAddress.cs

[Serializable]
    public class EmailAddress : IComparable<EmailAddress>
    {
        public const int MaxLength = 256;
// Regex based on Phil Haacks http://haacked.com/archive/2007/08/21/i-knew-how-to-validate-an-email-address-until-i.aspx
        public const string Expression = @"[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+(?:[A-Z]{2}|com|org|net|gov|mil|biz|info|mobi|name|aero|jobs|museum|uk)\b";
        private readonly string value;

        public EmailAddress(string value)
        {
            if (!Regex.IsMatch(value, Expression))
            {
                throw new ArgumentException(Resources.Common.Arg_NotValidEmailAddress, "value");
            }

            this.value = value;
        }

        public static bool IsValid(string value)
        {
            return Regex.IsMatch(value, Expression);
        }

        public int CompareTo(EmailAddress other)
        {
            return this.ToString().CompareTo(other.ToString());
        }

        public override string ToString()
        {
            return this.value;
        }

        public static bool TryParse(string value, out EmailAddress result)
        {
            if (IsValid(value))
            {
                result = new EmailAddress(value);
                return true;
            }

            result = null;
            return false;
        }
    }

Password.cs

// Uses SaltedHash from http://www.dijksterhuis.org/creating-salted-hash-values-in-c/
[Serializable]
    public struct Password : IComparable<Password>
    {
        public Password(string password, string salt) : this()
        {
            this.Value = password;
            this.Salt = salt;
        }

        public string Value
        {
            get;
            private set;
        }

        public string Salt
        {
            get;
            private set;
        }

        public static Password CreateFromClearText(string password)
        {
            string hashedPassword;
            string salt;

            var saltedHash = new SaltedHash();
            saltedHash.GetHashAndSaltString(password, out hashedPassword, out salt);

            return new Password(hashedPassword, salt);
        }

        public bool IsSameAs(string password)
        {
            var saltedHash = new SaltedHash();

            return saltedHash.VerifyHashString(password, this.Value, this.Salt);
        }

        public int CompareTo(Password other)
        {
            if (this.Salt.CompareTo(other.Salt) == 0 && this.Value.CompareTo(other.Value) == 0)
            {
                return 0;
            }

            return -1;
        }
    }