Dropping tables

DROP TABLE does not seem to allow me to fully drop a table. Example:

test=# CREATE TABLE x (id SERIAL);
NOTICE: CREATE TABLE will create implicit sequence 'x_id_seq' for SERIAL column 'x.id'
NOTICE: CREATE TABLE/UNIQUE will create implicit index 'x_id_key' for table 'x'CREATE

The notices look ominous, but I understand their meaning. OK. Now
say I want to drop the table:

test=# DROP TABLE x;
DROP

Cool. And now I want to create an `x' table again:

test=# CREATE TABLE x (id SERIAL);
NOTICE: CREATE TABLE will create implicit sequence 'x_id_seq' for SERIAL column 'x.id'
NOTICE: CREATE TABLE/UNIQUE will create implicit index 'x_id_key' for table 'x'
ERROR: Relation 'x_id_seq' already exists

Huh? What is this? Oh, x_id_key somehow survived DROP TABLE.
Bummer. Maybe I can use DROP INDEX to drop it?

test=# DROP INDEX x_id_seq;
ERROR: relation "x_id_seq" is of type "S"

Oh, x_id_seq is of type "S" -- of course I can't delete it. That was
a joke. Seriously, what am I supposed to do to get rid of it?

Or, better said, what do I do to completely and totally delete a
table?

I'm using what seems to be the latest postgresql package in Debian
"unstable" distribution. Version information follows:

test=# SELECT version();
version
---------------------------------------------------------------
PostgreSQL 7.0.0 on i686-pc-linux-gnu, compiled by gcc 2.95.2
(1 row)

$ dpkg -s post